Dissertations / Theses: 'Whispering gallery mode'

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YU, LILI. "Thermometry based on Whispering Gallery Mode resonators." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2497124.

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Whispering gallery (WG) mode resonators were studied since 1980s for precision clock oscillators and for cavity quantum electrodynamics studies. They are a kind of stable, high Q, microwave resonators where a symmetric dielectric medium, such as a cylinder or a disk, is suspended in the centre of a metal cavity. A coaxial cable or a waveguide are used to couple the EM field in the microwave region and thus to excite the system resonant frequencies. WG modes are resonant modes of higher-order azimuthal number (m) having most of the EM energy concentrated on the dielectric surface. Within the temperature range of -196 °C to 500 °C the most commonly used industrial thermometer is platinum resistance thermometer (PRT) with the uncertainties of 10 mK. The PRT offers high accuracy, low drift, a wide operating range; however, it is very sensitive to mechanical shock in handing and shipping. Besides, an AC resistance bridge which is typically required as a readout device for PRT is very expensive. Accordingly, there is a great need for a stability-improved, resistant to mechanical shock, potential lower uncertainty and cost-effective industrial thermometer. WGMR thermometer (WGMRT) is a new kind of thermometer which offers greater vibration immunity, improved stability, smaller uncertainty in temperature measurement and potential lower cost than platinum resistance thermometry. An innovative sapphire whispering gallery thermometer (SWGT) was first explored at the National Institute of Standards and Technology (NIST) in 2007 by Strouse [1] with the uncertainty less than 10 mK. Five WGMs with nominal resonant frequencies ranging from 14.4 GHz to 19.1 GHz and with Q-factors, respectively, ranging from 20,000 to 90,000 were measured within the temperature range of 0 °C to 100 °C. The accuracies of his WGMTs were in the range of ± 0.02 °C and ice point repeatability was better than 2 mK. The thesis reports the tests performed on several WGMR thermometers which have different shapes of crystals to evaluate their stability, resolution and repeatability in the temperature range of -40 °C to 85°C. Thermal cycle experimental results IV showed a Q in excess of 100000 for the mode with the highest azimuthal number, making it possible to achieve a potential temperature resolution of 0.1 mK. Besides, different specimens of crystals with the same nominal specification and reassemble for the same specimen were both tested to check the reproducibility of the thermometer. The birefringence of the sapphire was also studied to make an innovative thermometer. The ratios of two doublet frequencies are sensitive to the temperature-dependent birefringence of the crystal and relatively insensitive to surface contamination and changes in the shape of the cavity. Besides, it can have an external shape that closely approximates the shape of conventional platinum resistance thermometers.

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Li, Y. L. "Cooling and sensing using whispering gallery mode resonators." Thesis, University College London (University of London), 2016. http://discovery.ucl.ac.uk/1522162/.

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This thesis reports on a detailed exploration of the optomechanical interaction between a tapered optical fibre and a silica microsphere mounted on a cantilever. The amount of light evanescently coupled from the fibre into the optical whispering gallery mode of the sphere is exquisitely sensitive to their separation allowing fast measurement of picometre displacements of both the microsphere-cantilever and the fibre. By exploiting this enhanced transduction, strong active feedback damping/cooling of the thermal motion of both the fibre and microsphere-cantilever have been demonstrated to the noise limit of the system. The cavity enhanced optical dipole force between the fibre and the sphere was used to damp multiple mechanical modes of the tapered fibre, while a piezo-stack at the clamped end of the microsphere-cantilever allowed for cooling of its centre-of-mass motion and the second mechanical eigenmode. The effect of noise within the feedback loop was shown to invert the measured mechanical mode spectrum at high feedback gain as the noise itself is fed into the resonator. A rich variety of feedback induced spring stiffening and softening of the mode is measured when time delays are introduced. Cooling of the mechanical modes of the taper, which are ubiquitous to many whispering gallery mode experiments and are considered as unwanted noise, has not been achieved previously. Simultaneous operation of both feedback schemes was demonstrated for the first time, providing stabilization of the system. By using the microsphere-cantilever as an inertial test mass, measurement of its displacement induced by acceleration can resolve micro-g accelerations at high bandwidth.

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Hajjiah, Ali T. "Design and Analysis of Whispering Gallery Mode Semiconductor Lasers." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26136.

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Significant technical barriers currently prevent the wide spread adoption of WGM lasers as building blocks in large-scale photonic integrated circuits. The first challenge is to reduce the electrical power consumption at desirable levels of light output power. The second target is to obtain directional light emission without sacrificing other laser performance metrics. The best opportunity for success lies in the pursuit of small micro-Pillar lasers with spiral-geometry cavities. Process technology has been demonstrated for making high-performance WGM lasers including a refined ICP etching process for fabricating micro-Pillar cavities with sidewall roughness less than 10 nm and a new hydrogenation based approach to achieving current blocking that is compatible with all other processing steps and robust in comparison with earlier reports. A comprehensive photo-mask has been designed that enables investigation of the interplay between device geometry and WGM laser performance. Emphasis has been placed on enabling experiments to determining the impact of diffraction and scattering losses, current and carrier confinement, and surface recombination on electrical/optical device characteristics. In addition, a methodology has been developed for separating out process optimization work from the task of identifying the best means for directional light out-coupling. Our device fabrication methods can be proven on WGM lasers with pure cylindrical symmetry, hence results from these experiments should be independent of any specific light output coupling scheme. Particular attention has been paid to the fact that device geometries that give the best performance for purely symmetrical cavities may not yield the highest level of light emission from the spiral output notch. Such considerations seem to be missing from much of the earlier work reported in the literature. Finally, our processing techniques and device designs have resulted in individual WGM lasers that outperform those made by competitors. These devices have been incorporated into multi-element, coupled-cavity optical circuits thereby laying the groundwork for construction of digital photonic gates that execute AND, OR, and NOT logic functions.
Ph. D.

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Panich, Sirirat. "Optical resonance sensors based on whispering-gallery-mode technique." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/48497.

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In recent years, the whispering gallery mode (WGM) technique has received considerable attention as a novel and extremely sensitive technique for use in sensors. The technique is able to detect target molecules at very low levels and in real time, a capability which cannot be matched by any other detection technique currently in use. With this potential rarely found in common sensors, WGM is becoming one of the most widely used. The WGM set-up is simple and inexpensive. Light generated by a tunable laser, circumnavigates the surface of a resonator through a tapered waveguide. This light is strongly confined inside the microresonator by total internal reflection (TIR). Energy is extracted from the fibre, resulting in a negative peak. The surface of the resonator needs to be functionalised for reacting with the target molecule. If a chemical or biological analyte is to be bound on the surface of the resonator, the negative peak must be shifted. This shift can be used for measuring the amount of the analyte. In view of its exciting potential, it is not surprising that WGM is establishing itself as the detection method of choice, especially in chemical and biomedical applications. The work reported in this thesis is in two sections. In the first part, the use of the WGM technique integrated self-assembled glutathione (GSH) modified gold nanoparticles (Au NPs) on an optical microsphere resonator in an ultrasensitive chemical detection assay for Pb(II) (down to 10 ppt or 0.05 nM) is described. This satisfies the demanding sensitivity required for monitoring the maximum Pb(II) exposure limits set by both International Agency for Research on Cancer (IARC) and the United States Environmental Protection Agency (EPA). The second section presents an example of the use of WGM in a biosensor to study the interactions between small molecules and G-quadruplex DNA which is well known to be active targets for anticancer treatments. Currently methods typically used to study such systems have proven to be valuable; however, they have limitations, such as low sensitivity, time-consuming monitoring and lack of real time analysis. To circumvent these problems, a novel platform based around WGM is developed. The sensor offers a real time, fast and sensitive analysis. In addition, kinetic data such as dissociation equilibrium constant (KD ) as well as association and dissociation constant (kon and koff , respectively) can be easily obtained.

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Sedlmeir, Florian [Verfasser], and Harald [Gutachter] Schwefel. "Crystalline Whispering Gallery Mode Resonators / Florian Sedlmeir ; Gutachter: Harald Schwefel." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2016. http://d-nb.info/1127336525/34.

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Norris, Gavin J. R. "Whispering Gallery mode lasers for the mid-infrared spectral range." Thesis, Lancaster University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441779.

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Fraser, Michael John. "Optical Fiber Microstructures for Self-Contained Whispering Gallery Mode Excitation." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/73659.

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Optical resonators, which confine light by resonant recirculation, serve as the basis for a wide variety of optical components. Though they appear in many geometric forms, the most effective of optical resonators show axial symmetry in at least one dimension. A popular variation that finds broad application is the dielectric sphere. Acclaimed for their high quality (Q) factor and small modal volume, spheres owe credit of these attractive features to their support of whispering gallery mode (WGM) resonances. The sensitivity of a resonance's frequency and Q to strain, temperature, and other parameters of the surrounding medium can be the basis for ultracompact modulators and sensors. Physically, WGMs are special optical modes which can be understood as light rays that orbit the equator of the sphere guided by total internal reflection. Like a smooth stone can be skipped along the surface of a pond, light can be confined to the inside of a sphere by successive reflections. To best excite WGMs, the source light should initially trace a line tangent to the sphere's circumference. But incorporating a tiny sphere with such nanometric tolerances into a practical sensor structure has its challenges and the prospects for microsphere applications have suffered because of the plight of this problem. The work in this dissertation details the fabrication and function of three new "press fit" spherical resonators. These etched fiber micro-devices were developed to meet the demand for a robust, self-integrated means of coupling light between an optical fiber and WGMs in a microsphere resonator. The etching processes have been tuned to enable secure storage of a microsphere while also providing efficient excitation and interrogation of WGMs. Furthermore, the methods have been designed to be staightforward, quick, and repeatable. Using standard etchants on common polarization-maintaining fiber with readily purchased microspheres, the press fit resonators demonstrated here can be batch-fabricated and assembled. The press fit spherical resonator offers an alignment-free and conveniently pigtailed WGM coupler that has great potential for bio-science sensing applications and studies of resonant bispheres.
Ph. D.

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Simons, Matthew Thomas. "Whispering-gallery mode resonators for nonlinear and quantum optical applications." W&M ScholarWorks, 2014. https://scholarworks.wm.edu/etd/1539624003.

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Quantum information is the next frontier in communications. to realize quantum communications, the quantum mechanical properties of today's best communication medium, light, must be harnessed in a scalable and efficient manner. Whispering-gallery mode resonators (WGMRs), a type of optical cavity, have advantages over traditional designs that can enhance processes used in the generation of nonclassical (quantum) states of light. In particular they reduce the power threshold for intensity-dependent nonlinear phenomena. One such process, second harmonic generation, can reduce the shot noise of light below the standard quantum limit. This dissertation explores the theoretical analysis and experimental tests of noise reduction through second harmonic generation in a crystalline whispering-gallery mode resonator. We also observe the generation of another nonlinear optical process, hyper-Raman scattering, at modest optical powers inside a crystalline WGMR. The change in optical properties of vanadium dioxide due to an optically-induced phase transition is also studied as a potential Q-switching material in a WGMR-type cavity.

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Pang, Shuo. "Whispering gallery modes in quantum dot-embedded dielectric microspheres for tagless remote refractometric sensing." Texas A&M University, 2008. http://hdl.handle.net/1969.1/85998.

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This thesis presents the development of a refractometric sensor based on quantum dot-embedded polystyrene microspheres. The technique uses optical resonances within a microsphere, known as Whispering-Gallery Modes (WGMs), which produce narrow spectral peaks. The basic theory of WGMs is reviewed and specifically discussed for biosensing application. The spectral shifts of WGM peaks are sensitive to changes in the local refractive index. In the experiments, two-photon excited luminescence from the quantum dots couples into several WGMs within the microresonator. By optimizing the detection area, the spectral visibility of the WGMs is improved. The spectral shifts are measured as the surrounding index of refraction changes. The experimental sensitivity is about five times greater than that predicted by Mie theory. The sensor element is based on commercially available dielectric microspheres with a diameter about 10 μm. Thus, the technique is more economic and suitable for sensing applications, compared to microspheres of 100 μm in size which can only be made in the laboratory.

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Cheema, Muhammad. "Towards optimal whispering gallery mode microcavity sensors: novel techniques and analyses." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121389.

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The last two decades have seen tremendous progress towards the development of real time, label free and sensitive optical sensors. Researchers have demonstrated numerous techniques based on surface plasmon resonance, interferometers, waveguides, microcavities, optical fibers and photonic crystals. Among these different approaches, the large photon lifetime (quality factor of 10^6-10^9) of whispering gallery mode (WGM) microcavities makes them a strong candidate for ultrasensitive sensing, as the circulating photons sample a sensing event many times. In a microcavity sensor, the sensing event can be correlated to various measurement parameters including the resonant wavelength and the quality factor. A variety of approaches have been introduced to measure these parameters but little attention has been previously paid to improve the overall signal to noise ratio or accuracy of the sensor. The existing approaches suffer from various drawbacks; some of them do not allow for real time measurement, and their signal (change in the cavity parameters in response to the sensing event) is limited by many noise sources such as laser intensity noise and wavelength instability. Moreover, it is often assumed in the literature that optimum sensing performance is obtained by operating a microcavity at its highest possible quality factor. However, this does not consider the impact of the quality factor on the signal to noise ratio of the sensor. Finally, previous investigations have not explored the opportunity to combine measurements of two different microcavity parameters (i.e. resonant wavelength and quality factor) in order to obtain a more accurate estimation of a sensing event.In this thesis our goal is to develop techniques and analyses towards optimal performance of WGM microcavity sensors. To achieve this goal, firstly, we demonstrate a novel measurement approach for the microcavity sensors based upon phase shift-cavity ring down spectroscopy. We show that it is possible to simultaneously measure the resonant wavelength and the quality factor of a microcavity as a function of the sensing event, in real time and with high noise immunity. Secondly, we develop an accurate electromagnetic model to calculate the resonant wavelength and the quality factor for any axisymmetric microcavity geometry. The model is utilized to determine the microcavity parameters for obtaining the maximum signal of the sensor. Thirdly, we conduct a comprehensive noise analysis for those microcavity sensors that measure changes in the resonant wavelength and the quality factor to probe a sensing event. The signal and noise analysis shows that there is an optimal size and quality factor for a microcavity at which the maximum signal to noise ratio (SNR) is obtained, and that a highest quality factor may not result in the highest SNR. Finally, we develop a model and demonstrate that a combination of the resonant wavelength and the quality factor measurements of a microcavity sensor provide a more accurate sensing approach. The model is also extended to develop a sensing metric to compare the performance of wide range of sensors. Significantly, except for the electromagnetic model which applies to any axisymmetric WGM microcavity, all the techniques and the analyses developed in this thesis are independent of the WGM microcavity geometry. Moreover, the electromagnetic model, the signal and the noise analysis, and the work on combining the multiple sensing parameters are also applicable to the previously demonstrated approaches. Furthermore, the current work is relevant to various sensing applications, ranging from liquid to gaseous phase. We believe that the present thesis is a step forward towards optimal performance for WGM microcavity sensors.
la longue durée de vie du photon (facteur de qualité de 10^6-10^9) des microcavités en mode de chuchotement en galerie (WGM) font de celles-ci d'excellentes candidates pour la détection ultrasensible puisque les photons circulant dans la cavité échantillonnent le même évènement plusieurs fois. Dans un capteur à microcavité, l'évènement de détection peut être corrélé à plusieurs paramètres de mesures incluant la longueur d'onde de résonance et le facteur de qualité. Des approches variées ont été présentées pour mesurer ces paramètres mais l'amélioration du rapport signal sur bruit et la précision des capteurs ont reçu peu d'attention jusqu'à maintenant.Les approches existantes possèdent plusieurs inconvénients; certaines ne permettent pas de mesures en temps réel et leur signal (changement des paramètres de la cavité en réponse à l'évènement de détection) est limité par les multiples sources de bruit tels que l'intensité et l'instabilité de la longueur d'onde du laser. De plus, il n'a jamais été démontré que l'information à propos d'un évènement de détection puisse être déterminée plus précisément en utilisant une combinaison des multiples paramètres d'une microcavité, tels que la longueur d'onde de résonance et le facteur de qualité. En outre, il est souvent pris pour acquis dans la littérature que la performance optimale de détection est obtenue en opérant une microcavité à son facteur de qualité le plus élevé. Cependant, cette démarche ne prend pas compte de l'impact du facteur de qualité sur le rapport signal sur bruit du capteur. Dans cette thèse, notre objectif est de développer des techniques et des analyses pour une performance optimale des capteurs à microcavité WGM. Pour atteindre cet objectif, nous démontrons tout d'abord une nouvelle approche de mesure pour les capteurs basés sur la spectroscopie d'absorption par déphasage et mesure du temps de vie des photons piégés dans une cavité optique. Nous démontrons qu'il est possible de mesurer simultanément la longueur d'onde de résonance et le facteur de qualité de la microcavité en fonction de l'évènement de détection, en temps réel et avec une grande immunité au bruit. Deuxièmement, nous développons un modèle électromagnétique précis pour calculer la longueur d'onde de résonance et le facteur de qualité pour toutes les géométries asymétriques des microcavités. Le modèle est utilisé pour déterminer les paramètres de la microcavité afin d'obtenir un signal maximum avec le capteur. Troisièmement, nous effectuons une analyse compréhensive du bruit pour les capteurs à microcavité qui mesurent les changements dans la longueur d'onde de résonance et le facteur de qualité pour la détection. L'analyse du signal et du bruit démontre qu'il y a une dimension optimale et un facteur de qualité pour lesquels un rapport signal sur bruit (SNR) maximum est obtenu, et qu'un facteur de qualité plus élevé ne donne pas nécessairement un SNR plus élevé. Finalement, nous développons un modèle et démontrons qu'une combinaison de la mesure de la longueur d'onde de résonance et du facteur de qualité d'un capteur par microcavité fournit une détection plus précise. De plus, le modèle est étendu afin de développer un paramètre de détection pour comparer la performance de plusieurs capteurs. À l'exception du modèle électromagnétique qui s'applique à toutes les microcavités WGM asymétriques, toutes les techniques et analyses développées dans cette thèse sont indépendantes de la géométrie de la microcavité WGM. De plus, le modèle électromagnétique, l'analyse du signal et du bruit et les démonstrations sur la combinaison de multiples paramètres de détection s'appliquent aussi aux autres approches démontrées précédemment. En outre, la démarche présentée est appropriée pour plusieurs modes de détection, allant de la phase liquide à gazeuse. Nous croyons que la présente thèse est un pas de plus vers une performance optimale des capteurs à microcavité WGM.

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Auxemery, Philippe. "Contribution à l'étude des paramètres électriques et électromagnétiques des modes de galerie des résonateurs diélectriques." Limoges, 1989. http://www.theses.fr/1989LIMO4001.

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Deux méthodes d'analyses électromagnétiques des Whispering Gallery (W. G) modes des R. D. Sont présentées dans ce mémoire. Une méthode approximative analytique et la méthode des éléments finis permettent de connaître avec précision la fréquence de fonctionnement et la cartographie du champ électromagnétique d'une structure microonde. Ces résultats couplés à une analyse électrique des dispositifs à résonateurs diélectriques ont permis la réalisation de filtres directifs et d'un combineur de puissance utilisant les W. G. Modes des résonateurs diélectriques.

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[Verfasser], Assegid Mengistu Flatae, and H. [Akademischer Betreuer] Kalt. "Active Polymeric Whispering Gallery Mode Resonators / Assegid Mengistu Flatae. Betreuer: H. Kalt." Karlsruhe : KIT-Bibliothek, 2014. http://d-nb.info/1064940021/34.

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Großmann, Tobias [Verfasser], and H. [Akademischer Betreuer] Kalt. "Whispering-Gallery-Mode Lasing in Polymeric Microcavities / Tobias Großmann. Betreuer: H. Kalt." Karlsruhe : KIT-Bibliothek, 2012. http://d-nb.info/1032243082/34.

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Knight, Jonathan Cave. "Whispering-gallery-mode dye laser emission from liquid in a capillary fiber." Doctoral thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/17386.

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Bibliography: p. 153-170.
The nature of optical whispering-gallery-mode resonances in a layered microcylinder is investigated numerically by studying the scattering characteristics and the internal electromagnetic fields of a normally-illuminated cladded dielectric fiber calculated using the boundary-value method. Computed resonant mode configurations are compared to the better-known results for homogeneous spheres and cylinders and coated spheres. It is shown that high-Q whispering-gallery-mode resonances can be supported by the curved interface between the core and cladding regions of a layered fiber if the core refractive index is sufficiently greater than that of the outer layer, and that these modes can be directly related to the so-called morphology-dependent resonances of a homogeneous cylinder of the same size and relative refractive index as the fiber core. The implications of these resonant modes for inelastic optical processes are made clear by developing a model for optical emissions from a molecule in the core of a capillary fiber. The results of the model show that the transition rates of molecules in the fiber core and near to the core/cladding interface are enhanced at frequencies corresponding to cavity resonances. It is shown experimentally that these high-Q cavity modes can be excited to above the threshold for laser emission by providing gain in the fiber core material. We have used a refractive dye-doped solvent as a gain medium and a fused-silica capillary to form the resonant cavity. Upon optical excitation of the dye by illuminating the fiber normally with the green beam from a frequency-doubled Nd:YAG laser, laser emission is emitted from the fiber core in the plane perpendicular to the fiber axis. We explain the novel spatial and spectral dependences of the laser emission in terms of the calculated frequencies and Q-values of the resonant cavity modes and the bulk properties of the cavity medium. We show that the thresholds observed in the laser system can be explained using a simplified rate-equation approach, and that this also explains some of the other observed features of the emissions. The heating of the dye solvent during a laser pulse has an observable effect on the resonance mode locations due to the temperature dependence of the refractive index. We demonstrate the use of observed laser spectra to determine the size and taper of the capillary fiber core.

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Schließer, Albert. "Cavity optomechanics and optical frequency comb generation with silica whispering-gallery-mode microresonators." Diss., München Hut, 2009. http://edoc.ub.uni-muenchen.de/10940/.

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Cherenack, K. H. (Kunigunde Hadelinde). "Modelling of layered cylindrical dielectric resonators with reference to whispering gallery mode resonators." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52942.

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Thesis (MScEng)--University of Stellenbosch, 2002.
ENGLISH ABSTRACT: Keywords: Dielectric Resonators, Radial Mode Matching, Whispering Gallery Modes The aim of this investigation was to develop accurate modelling techniques to determine the resonant frequencies of dielectric resonators. These resonators could be simple dielectric posts, rings or combinations of these two. To do this, a radial mode matching technique was implemented and applied to a post resonator, a ring resonator and finally a combination of the two. The resulting method was used to develop a model of a high-Q whispering gallery mode resonator consisting of a post and a ring resonator combination with an spurious free region region.
AFRIKAANSE OPSOMMING: Sleutelwoorde Dielektriese Resoneerders, Radiale Modale-Pas Tegniek, 'Whispering Gallery' Modus Die doel van hierdie navorsing was om 'n akkurate tegniek te ontwikkelom die resonante frekwensie van 'n dielektriese resoneerder vas te stel. Hierdie resoneerders kon eenvoudige resoneerders, ring resoneerders of kombinasies van die twee wees. 'n Radiale Modale-Pas tegniek is vir hierdie doel geïmplementeer en is op 'n eenvoudige resoneerder, 'n ring-resoneerder en kombinasies van die twee toegepas. Hierdie tegniek is dan gebruik om 'n hoë-Q resoneerder te ontwerp wat gebruik maak van 'n 'whispering gallery' modus. In hierdie geval is die resoneerder 'n kombinasie van 'n pil en 'n ring-resoneerder.

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Anstie, James D. "A 50 K dual-mode sapphire oscillator and whispering spherical mode oscillators." University of Western Australia. School of Physics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0070.

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[Truncated abstract] This thesis is split into two parts. In part one; A 50 K dual mode oscillator, the aim of the project was to build a 50 K precision oscillator with frequency stability on the order of 1014 from 1 to 100 seconds. A dual-mode temperature compensation technique was used that relied on a turning point in the frequency-temperature relationship of the difference frequency between two orthogonal whispering gallery modes in a single sapphire crystal. A cylindrical sapphire loaded copper cavity resonator was designed, modelled and built with a turning point in the difference frequency between an E-mode and H-mode pair at approximately 52.5 K . . . The frequencies and Q-factors of whispering spherical modes in the 3-12 GHz range in the fused silica resonator are measured at 6, 77 and 300 K and the Q-factor is used to determine the loss tangent at these temperatures. The frequency and Q-factor temperature dependence of the TM2,1,2 whispering gallery mode at 5.18 GHZ is used to characterise the loss tangent and relative permittivity of the fused silica from 4-300 K. Below 22 K the frequency-temperature dependence of the resonator was found to be consistent with the combined effects of the thermal properties of the dielectric and the influence of an unknown paramagnetic impurity, with a spin resonance frequency at about 138 ± 31 GHz. Below 8 K the loss tangent exhibited a 9th order power law temperature dependence, which may be explained by Raman scattering of Phonons from the paramagnetic impurity ions. A spherical Bragg reflector resonator made from multiple concentric dielectric layers loaded in a spherical cavity that enables confinement of field in the centre of the resonator is described. A set of simultaneous equations is derived that allow the calculation of the required dimensions and resonance frequency for such a resonator and the solution is confirmed using finite element analysis. A spherical Bragg reflector resonator is constructed using Teflon and free-space as the dielectric materials. A Q-factor of 22,000 at 13.87 GHz was measured and found to compare well with the design values.

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Wilson, Kerry. "APPLICATION OF ALKYLSILANE SELF-ASSEMBLED MONOLAYERS FOR CELLPATTERNING AND DEVELOPMENT OF BIOLOCIAL MICROELECTROMECHANICALSYSTE." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2605.

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Advances in microfabrication and surface chemistry techniques have provided a new paradigm for the creation of in vitro systems for studying problems in biology and medicine in ways that were previously not practical. The ability to create devices with micro- to nano-scale dimensions provides the opportunity to non-invasively interrogate and monitor biological cells and tissue in large arrays and in a high-throughput manner. These systems hold the potential to, in time, revolutionize the way problems in biology and medicine are studied in the form of point-of-care devices, lab-on-chip devices, and biological microelectromechanical systems (BioMEMS). With new in vitro models, it will be possible to reduce the overall cost of medical and biological research by performing high-throughput experiments while maintaining control over a wide variety of experimental variables. A critical aspect of developing these sorts of systems, however, is controlling the device/tissue interface. The surface chemistry of cell-biomaterial and protein-biomaterial interactions is critical for long-term efficacy and function of such devices. The work presented here is focused on the application of surface and analytical chemistry techniques for better understanding the interface of biological elements with silica substrates and the development a novel Bio-MEMS device for studying muscle and neuromuscular biology. A novel surface patterning technique based on the use of a polyethylene glycol (PEG) silane self-assembled monolayer (SAM) as a cytophobic surface and the amine-terminated silane diethyeletriamine (DETA) as a cytophilic surface was developed for patterning a variety of cell types (e.g. skeletal muscle, and neural cells) over long periods of time (over 40 days) with high fidelity to the patterns. This method was then used to pattern embryonic rat skeletal muscle and motor neurons onto microfabricated silicon cantilevers creating a novel biological microelectromechanical system (BioMEMS) for studying muscle and the neuromuscular junction. This device was then used to study the effect of exogenously applied substances such as growth factors and toxins. Furthermore, a whispering-gallery mode (WGM) biosensor was developed for measuring the adsorption of various proteins onto glass microspheres coated with selected silane SAMS commonly used in BioMEMS system. With this biosensor it was possible to measure the kinetics of protein adsorption onto alkylsilane SAMS, in a real-time and label-free manner.
Ph.D.
Department of Chemistry
Sciences
Chemistry PhD

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Cheng, Weifeng. "Development of High-Performance Optofluidic Sensors on Micro/Nanostructured Surfaces." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/103873.

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Optofluidic sensing utilizes the advantages of both microfluidic and optical science to achieve tunable and reconfigurable high-performance sensing purpose, which has established itself as a new and dynamic research field for exciting developments at the interface of photonics, microfluidics, and the life sciences. With the trend of developing miniaturized electronic devices and integrating multi-functional units on lab-on-a-chip instruments, more and more desires request for novel and powerful approaches to integrating optical elements and fluids on the same chip-scale system in recent years. By taking advantage of the electrowetting phenomenon, the wettability of liquid droplet on micro/nano-structured surfaces and the Leidenfrost effect, this doctoral research focuses on developing high-performance optofluidic sensing systems, including optical beam adaptive steering, whispering gallery mode (WGM) optical sensing, and surface-enhanced Raman spectroscopy (SERS) sensing. A watermill-like beam steering system is developed that can adaptively guide concentrating optical beam to targeted receivers. The system comprises a liquid droplet actuation mechanism based on electrowetting-on-dielectric, a superlattice-structured rotation hub, and an enhanced optical reflecting membrane. The specular reflector can be adaptively tuned within the lateral orientation of 360°, and the steering speed can reach ~353.5°/s. This work demonstrates the feasibility of driving a macro-size solid structure with liquid microdroplets, opening a new avenue for developing reconfigurable components such as optical switches in next-generation sensor network. Furthermore, the WGM sensing system is demonstrated to be stimulated along the meridian plane of a liquid microdroplet, instead of equatorial plane, resting on a properly designed nanostructured chip surface. The unavoidable deformation along the meridian rim of the sessile microdroplet can be controlled and regulated by tailoring the nanopillar structures and their associated hydrophobicity. The nanostructured superhydrophobic chip surface and its impact on the microdroplet morphology are modeled by Surface Evolver (SE), which is subsequently validated by the Cassie-Wenzel theory of wetting. The influence of the microdroplet morphology on the optical characteristics of WGMs is further numerically studied using the Finite-Difference Time-Domain method (FDTD) and it is found that meridian WGMs with intrinsic quality factor Q exceeding 104 can exist. Importantly, such meridian WGMs can be efficiently excited by a waveguiding structure embedded in the planar chip, which could significantly reduce the overall system complexity by eliminating conventional mechanical coupling parts. Our simulation results also demonstrate that this optofluidic resonator can achieve a sensitivity as high as 530 nm/RIU. This on-chip coupling scheme could pave the way for developing lab-on-a-chip resonators for high-resolution sensing of trace analytes in various applications ranging from chemical detections, biological reaction processes to environmental protection. Lastly, this research reports a new type of high-performance SERS substrate with nanolaminated plasmonic nanostructures patterned on a hierarchical micro/nanostructured surface, which demonstrates SERS enhancement factor as high as 1.8 x 107. Different from the current SERS substrates which heavily relies on durability-poor surface structure modifications and various chemical coatings on the platform surfaces which can deteriorate the SERS enhancement factor (EF) as the coating materials may block hot spots, the Leidenfrost effect-inspired evaporation approach is proposed to minimize the analyte deposition area and maximize the analyte concentration on the SERS sensing substrate. By intentionally regulating the temperature of the SERS substrate during evaporation process, the Rhodamine 6G (R6G) molecules inside a droplet with an initial concentration of 10-9 M is deposited within an area of 450 μm2, and can be successfully detected with a practical detection time of 0.1 s and a low excitation power of 1.3 mW.
Doctor of Philosophy
Over the past two decades, optofluidics has emerged and established itself as a new and exciting research field for novel sensing technique development at the intersection of photonics, microfluidics and the life sciences. The strong desire for developing miniaturized lab-on-a-chip devices and instruments has led to novel and powerful approaches to integrating optical elements and fluids on the same chip-scale systems. By taking advantage of the electrowetting phenomenon, the wettability of liquid droplet on micro/nano-structured surfaces and the Leidenfrost effect, this doctoral program focuses on developing high-performance optofluidic sensing systems, including optical beam adaptive steering, whispering gallery mode (WGM) optical sensing, and surface-enhanced Raman spectroscopy (SERS) sensing. During this doctoral program, a rotary electrowetting-on-dielectric (EWOD) beam steering system was first fabricated and developed with a wide lateral steering range of 360° and a fast steering speed of 353.5°/s, which can be applied in telecommunication systems or lidar systems. Next, the meridian WGM optical sensing system was optically simulated using finite difference time domain (FDTD) method and was numerically validated to achieve a high quality-factor Q exceeding 104 and a high refractive index sensitivity of 530 nm/RIU, which can be applied to the broad areas of liquid identification or single molecule detection. Lastly, a SERS sensing platform based on a hierarchical micro/nano-structured surface was accomplished to exhibit a decent SERS enhancement factor (EF) of 1.81 x 107. The contact angle of water droplet on the SERS substrate is 134° with contact angle hysteresis of ~32°. Therefore, by carefully controlling the SERS surface temperature, we employed Leidenfrost evaporation to concentrate the analytes within an extremely small region, enabling the high-resolution detection of analytes with an ultra-low concentration of ~10-9 M.

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Otterpohl, Alexander [Verfasser], Christoph [Akademischer Betreuer] Marquardt, Christoph [Gutachter] Marquardt, and Zanthier Joachim [Gutachter] von. "Squeezed vacuum states of light from a crystalline whispering gallery mode resonator / Alexander Otterpohl ; Gutachter: Christoph Marquardt, Joachim von Zanthier ; Betreuer: Christoph Marquardt." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2020. http://d-nb.info/1223175278/34.

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GUGLIANDOLO, GIOVANNI. "Applications of Microwave Resonators to Thermal Metrology." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2849028.

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Ceppe, Jean-Baptiste. "Éléments de dynamique du laser pour l'élaboration d'une source micro-onde miniaturisée sur la base de la double émission monomode d'un laser à mode de galerie." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S067/document.

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Ces travaux de thèses portent sur l’étude de la dynamique du laser à mode de galerie dans le but de réaliser une source micro-onde en utilisant un laser à mode de galerie doublement monomode. Nous montrons ici les résultats expérimentaux sur le bruit relatif d’intensité (RIN) d’un laser à mode de galerie en verre ZBLALiP dopé aux ions Er3+. Outre l’aspect performances d’utilisation du laser, le spectre de RIN donne un certain nombre d’informations sur la dynamique du laser (temps de vie des photons, taux de pompage effectif, sources de bruit, ...).Les très forts facteur de qualités de ces résonateurs ainsi que leurs propriétés de confinement spatial amène un couplage non-linéaire etre les photons et les atomes du milieu amplificateur, faisant apparaitre dans le spectre de RIN des harmoniques de la fréquence de relaxation du laser. Le modèle harmonique développé permet d’estimer le volume de mode du mode de galerie en régime laser, quantité difficilement estimable dans ce régime d’émission. D’autre part, les mesures de RIN réalisées sur un verre industriel IOG-1 codopé Yb3+/Er3+ montrent la signature d’un couplage modal, induit par la diffusion Rayleigh, où les deux modes couplés fonctionnent au dessus du seuil laser. La dynamique de ce laser est également étudié et les comportements obtenus sont mis en parallèle avec les études réalisées sur le gyro-Laser à l’état solide
This thesis presents the studies of whispering gallery mode laser dynamics in order to realize a micro-wave source using simultaneous oscillations in a unique whispering gallery mode micro-laser. We show experimental results on the relative intensity noise (RIN) of a Whispering Gallery Mode Laser in ZBLALiP glass doped with Er3+ ions. Besides the pure laser specifications, the RIN spectrum gives informations about the dynamics inside the cavity, such as photon lifetime, effective pumping rate and noise sources. Moreover, we have shown that a single-mode emission comes with the presence of multiple harmonics of the relaxation frequency. The theoretical model taking account the non-linear coupling between photons and atoms allows us to determine the mode volume of the whispering gallery mode in laser regime, which is quite difficult to evaluate in this regime. On the other hand, we have studied the laser dynamics in an industrial IOG-1 glass codoped with Yb3+/Er3+ ions where the signature of a modal coupling, induced by Rayleigh scattering, lies in the RIN spectrum. In this particular case, the two coupled modes operate above threshold. The observed behavior is compared with thoses of a solid state gyro-laser

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23

Yue, HongQuan. "Optical whispering gallery modes in chalcogenide As2Se3 microspheres." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104591.

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Anisotropic chalcogenide microsphere is introduced for coupling theoretical analyzing and coupling experiment. Whispering Gallery Modes (WGMs) of isotropic microsphere is introduced and the TE & TM WGMs dispersion relationship is derived from electromagnetic vector equations in the spherical coordinate. The Maxwell equations can be solved in 2D model for the 3D model of axisymmetric or Rotational symmetry isotropic microsphere. First 4 TE&TM WGMs are simulated in 2D model using finite-element weak method. The binding capability, mode volume V and quality factor Q depend on the refractive index and size of the microsphere. Plane wavefront light wave is assumed to propagate inside the microsphere; coupling coefficient is determined by WGMs numbers and the distance between the microsphere and the micro-taper. Coupling related Q factor is analyzed; TE & TM nonlinear microsphere coupling is introduced with Matlab simulation. Chalcogenide coupling experiments for transmission, reflection and drop-port function are conducted. The light waves for coupling are broadband incoherent light source and narrowband tunable laser. Broadband light gave sensitive results while the coherent laser gave easy coupling capability.The chalcogenide microsphere was used as a feedback element of an amplifying medium. Comparing with silica microsphere, chalcogenide microsphere?s response is more unstable due to free carriers perturbation and thermal activity.
Cette thèse présente une analyse théorique et expérimentale du couplage des microsphères anisotropes en verre de chalcogénure. Les modes de galerie résonants (WGMS) de microsphères isotrope sont aussi présentés et la relation de dispersion TE et TM des WGMS est dérivée à partir des équations vectorielles électromagnétiques en coordonnées sphériques. Les équations de Maxwell peuvent être résolues en 2D pour la résolution en 3D de microsphères axisymétriques ou a symétrie rotationnelle isotrope. Les quatre premiers WGMS TE et TM sont simulés dans le modèle 2D en utilisant la méthode des éléments finis. La capacité de liaison, le volume modal V et facteur de qualité Q dépendent de l'indice de réfraction et de la taille de la microsphère. On décompose une onde lumineuse en multiples fronts d'onde plan à l'intérieur de la microsphère; le coefficient de couplage entre une microsphère et un microfil est déterminé par le nombre de WGMS et la distance entre la microsphère et microfil. Le facteur de qualité Q est analysé; le couplage TE & TM de microsphères non linéaire est introduit à partir de simulations Matlab. Des expériences de couplage pour la transmission, la réflexion et le port à fonction «drop» sont conduites. Les ondes lumineuses pour le couplage proviennent d'une source de lumière à large bande incohérent et d'une source laser étroite accordable à bande étroite. La lumière à large bande a donné des résultats à haute sensibilité tandis que le laser cohérent facilite la mesure de couplage.En dernier lieu, les microsphères de chalcogénure ont été utilisées comme élément de rétroaction pour un milieu amplificateur. En comparaison avec des microsphères de silice, les microsphères de chalcogénure génèrent une réponse qui est plus instable due à la perturbation par les porteurs libres et l'activité thermique.

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Aubry, Guillaume. "Microresonateurs optiques à etat liquide et microfluidique digitale : applications aux lasers à colorant en gouttes pour les laboratoires-sur-puce." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00664670.

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L'objectif de ce travail porte sur l'étude et la réalisation de résonateurs optiques à état liquide en microfluidique digitale. Les gouttes sphériques constituent des résonateurs à mode de galerie, dans lesquels la lumière peut être piégée par réflexion totale interne. A l'échelle microscopique, elles exhibent des propriétés optiques remarquables. Leurs facteurs de qualité très élevés en font notamment des objets propices à l'étude de phénomènes optiques non linéaires, tel l'effet laser, et leur confèrent un potentiel certain en spectroscopie. Par ailleurs, la microfluidique digitale, qui a trait aux systèmes multiphasiques dans des microcanaux artificiels, offre une grande liberté de manipulation des microgouttes : génération au kHz, transport, encapsulation, fusion, division, stockage, triage... Aussi, pour les laboratoires-sur-puce, le développement de ces microgouttes en cavités résonantes constitue une opportunité d'intégrer des outils d'analyse optique capables de sonder des échantillons allant du picolitre au nanolitre.Après un exposé des propriétés optiques des résonateurs à modes de galerie, ce mémoire rapporte les travaux réalisés. Une présentation des méthodes de microfabrication et du montage expérimental précède l'étude de la génération de cavités optiques liquides en dynamique. Ces cavités résonantes sont ensuite appliquées aux sources lasers microfluidiques. En particulier, un effet laser a été mis en évidence dans des microgouttes sphériques d'éthylène glycol contenant de la rhodamine 6G. Enfin, une ouverture sur des systèmes couplant microgouttes et cavités Fabry-Perot présente d'autres perspectives telles que l'analyse de gouttes passives en intravité laser ou bien la commutation rapide de la longueur d'onde d'émission de lasers microfluidiques monomodes.

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Foster, David H. "Fabry-Perot and Whispering Gallery Modes In Realistic Resonator Models." Thesis, view abstract or download file of text, 2006. http://wwwlib.umi.com/cr/uoregon/fullcit?p3211216.

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Thesis (Ph. D.)--University of Oregon, 2006.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 204-213). Also available for download via the World Wide Web; free to University of Oregon users.

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Dinyari, Khodadad. "Coupling Nitrogen Vacancy Centers in Diamond Nanopillars Whispering Gallery Microresonators." Thesis, University of Oregon, 2013. http://hdl.handle.net/1794/12962.

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For cavity quantum electrodynamics systems (cavity-QED) to play a role in quantum information processing applications and in quantum networks, they must be robust and scalable in addition to having a suitable method for the generation, processing and storage of quantum bits. One solution is to develop a composite system that couples a nitrogen vacancy (NV) center in diamond to a whispering gallery mode supported by a fused silica microsphere. Such a system is motivated by the optical and electron-spin properties of the NV center. The NV center is the leading spin-qubit and exhibits atomic like linewidths at cryogenic temperatures and has spin coherence times greater than milliseconds at room temperature. These long coherence times, coupled with nanosecond scale spin readout and manipulation times, allow for millions of quantum operations to be processed. Silica whispering gallery resonators are the only class of microresonators with quality factor high enough to reach the strong coupling regime, which is necessary for some quantum information processing applications. Integrating these two components into a system that could position a diamond nanopillar near the surface of a deformed-double stemmed microsphere system, with nanometer precision, at 10 K was a major achievement of this research. Cavity resonances in deformed microspheres can be excited with a free-space coupling technique which simplifies their integration into cryogenic environments. In these intentionally deformed resonators, an enhanced evanescent field decay length was observed at specific locations along the ray orbit. The double-stem arrangement enables the cavity resonance to be tuned over 450 GHz, with sub-10 MHz resolution, at 10 K. These two features, the enhanced decay length and broad range tuning with high resolution, are indispensible tools for cavity-QED studies with silica microspheres. Diamond nanopillars were fabricated from single crystal diamond with diameters as small as 140 nm in order to maintain a high quality factor. Studies were conducted on NV centers in nanopillars and bulk diamond to determine their suitability for cavity-QED applications. In an attempt to increase the light-matter interaction between NV centers and whispering gallery modes, diamond substrates were optically characterized that were irradiated with nitrogen ions.

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Lafleur, Gaël. "Nouvelles architectures de composants photoniques par l'ingénierie du confinement électrique et optique." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30263/document.

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Le confinement électrique et optique par oxydation des couches minces d'AlGaAs est une étape essentielle dans la réalisation des composants photoniques actifs et passifs dans la filière de matériaux GaAs. La recherche de performances ultimes sur ces composants nécessite une meilleure maîtrise du procédé d'oxydation ainsi qu'une meilleure connaissance des propriétés optiques de l'oxyde d'aluminium (AlOx). Dans cette perspective, j'ai d'abord réalisé une étude expérimentale de la vitesse d'oxydation des couches d'AlGaAs en fonction de la température du substrat, de la composition en gallium des couches étudiées, de la pression atmosphérique et de la géométrie des mesas considérés. Puis, j'ai établi un modèle anisotrope permettant une meilleure résolution spatiale et temporelle de la forme du front d'oxydation de l'AlAs. Enfin, j'ai exploité ce procédé pour réaliser des composants d'optique guidée notamment des micro-résonateurs puis réalisé des guides optiques à fente et caractérisé leurs performances optiques
Optical and electrical confinement using Al(Ga)As layer oxidation is a key milestone in the fabrication of active and passive GaAs-based photonic components. To optimize those devices, through the control of the optical and electrical confinements, a better modelling of oxidation process and a better understanding of optical properties of aluminum oxide (AlOx) is required. One part of this work is focusing on a throughout experimental study of AlGaAs oxidation kinetics, where I studied different important parameters such as wafer temperature, gallium composition, atmospheric pressure and mesa geometry. Then, I developed a new predictive model taking into account the process anisotropy, thus allowing a better temporal and spatial of AlAs oxidation front evolution. Finally, I could exploit this technological process to realize whispering gallery mode microdisks as well as slot optical waveguides, and I have characterized this latter photonic devices

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Rasoloniaina, Alphonse. "Études expérimentales de dispositifs intégrés à base de micro-résonateurs à mode de galerie en verres actifs." Phd thesis, Université Rennes 1, 2014. http://tel.archives-ouvertes.fr/tel-01009345.

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Les microrésonateurs à mode de galerie passifs à base de cristal ou de verre fabriqués par la méthode de fusion possèdent un facteur de qualité limité à quelques 10E8. Ceci est généralement dû à la contamination de la surface du résonateur lors de sa fusion. Dans ces travaux, nous proposons de contourner cette limitation en utilisant des microrésonateurs actifs pour compenser les pertes. Afin de caractériser les microrésonateurs actifs de très haut facteur de qualité ainsi obtenu, nous nous appuyons sur la méthode CRDM (Cavity Ring Down Measurement). Cette méthode interférométrique est d'une part bien adaptée à la caractérisation de résonateurs de très haut facteur de qualité et d'autre part elle permet de remonter de manière univoque aux facteurs de qualité intrinsèque Qo et extrinsèque Qe du résonateur. Dans un régime de compensation de pertes, nous avons pu atteindre tous les régimes de couplage et obtenus des facteurs de qualité intrinsèques excédant les 10E10. En régime d'amplification sélective, nous avons démontré expérimentalement que l'on pouvait obtenir des gains élevés allant jusqu'à 33 dB et des retards de groupe excédant 2,3 µs dans ces microrésonateurs actifs. Ces microrésonateurs de très haut facteur de qualité et de très haute finesse peuvent présenter un couplage modal se manifestant par un doublet de résonances. Une confrontation théorie/expérience avec la méthode CRDM permet de mesurer un écart très faible entre les doublets. Par ailleurs, ces microrésonateurs présentant un fort confinement spatial et une forte surtension, sont propices à l'observation d'effets non-linéaires. Une modélisation intégrant l'effet thermique et l'effet Kerr a été réalisée. Une confrontation théorie/expérience nous a permis d'estimer la puissance réellement injectée dans le mode ainsi qu'à estimer le volume du mode.

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Klusmann, Carolin [Verfasser], and H. [Akademischer Betreuer] Kalt. "Hybrid Photonic–Plasmonic Modes in Coated Whispering-Gallery Resonators / Carolin Klusmann ; Betreuer: H. Kalt." Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1191267466/34.

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Tomazio, Nathália Beretta. "Fabricação de micro-ressonadores ópticos via fotopolimerização por absorção de dois fótons." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-14042016-140022/.

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Os micro-ressonadores que suportam whispering gallery modes têm atraído a atenção da comunidade científica devido a sua grande capacidade de confinar a luz, propriedade que faz dessas estruturas plataformas ideais para o desenvolvimento de pesquisa fundamental como interação da radiação com a matéria e óptica não linear. Além disso, suas características como operação em frequências do visível e de telecomunicações, facilidade de integração e alta sensitividade os tornam extremamente flexíveis para aplicações que vão desde filtros ópticos até sensores. Neste trabalho, demonstramos a fabricação de tais micro-ressonadores via fotopolimerização por absorção de dois fótons (FA2F). Esta técnica apresenta uma série de vantagens para a confecção de micro-dispositivos, sendo elas a capacidade de resolução inferior ao limite de difração, a flexibilidade de formas e ainda, a possibilidade de incorporar compostos de interesse à matriz polimérica a fim de introduzir novas funcionalidades ao material que compõe a estrutura final. Ademais, diferentes polímeros podem ser utilizados para a fabricação das microestruturas, tornando a técnica viável para uma vasta gama de aplicações. As microestruturas poliméricas que fabricamos são micro-cilindros ocos de boa integridade estrutural com 45 μm de diâmetro externo e 100 nm de rugosidade de superfície, o que as torna potencialmente aplicáveis como micro-ressonadores para frequências de operação típicas de telecomunicações. A fim de acoplar luz nessas estruturas, em colaboração com a Universidade de Valência, na Espanha, montamos um aparato de acoplamento. Neste aparato, a luz proveniente de uma fonte de luz centrada em 1540 nm é acoplada nos micro-ressonadores via campo evanescente por meio do uso de uma fibra óptica estirada de 1.5 μm de diâmetro. A potência transmitida é guiada para um analisador de espectro óptico, onde é possível identificar os modos ressonantes, representados como picos de atenuação com free spectral range em torno de 9.8 nm. Ao término desse projeto, um aparato similar foi montado no Grupo de Fotônica do IFSC/USP, a partir do qual pudemos medir os modos ressonantes tanto de fibras ópticas estiradas quanto dos micro-cilindros poliméricos. A finesse dos micro-ressonadores poliméricos caracterizados varia de 2.51 a 4.35, sendo da mesma ordem de grandeza do valor reportado na literatura para ressonadores de alta performance fabricados por FA2F a partir da mesma formulação de resina polimérica que utilizamos.
Whispering gallery modes microresonators have been attracting increasing interest due to their ability to strongly confine light within small dielectric volumes. This property is quite useful for basic research involving light-matter interaction and nonlinear optics, but their applications go beyond that. The ease of fabrication, on-chip integration and operation at telecommunication frequencies make them suitable for a variety of practical applications, including photonic filters and sensing. In the current work, we demonstrate the fabrication of such resonators via two-photon polymerization. Using this technique, complex 3D structures with submicrometer feature size can be produced. Besides, the flexibility of geometry and the possibility of incorporating a variety of additional materials, such as organic compounds make it a powerful tool for the fabrication of microresonators. The microstructures we have fabricated are 45 μm outer diameter hollow microcylinders, with good structural integrity and sidewall roughness estimated in 100 nm, which make their application as microresonators feasible in the near infrared wavelength regime. In order to couple light within these microresonators, an experimental setup was built at University of Valencia to implement the coupling. In this setup, light from a 1540 nm-centered broadband source was coupled into the fabricated microresonators via evanescent field using a 1.5 μm waist tapered fiber. The transmitted light was then guided to an optical spectral analyzer, where it was possible to measure resonances, represented as attenuation peaks, with free spectral range of about 9.8 nm. Afterwards, a similar experimental setup was assembled in the Photonics group at IFSC/USP, where we could observe resonances of both tapered optical fibers and the polymeric microresonators fabricated by means of two-photon polymerization. The finesse of the polymeric microresonators was estimated in 4.35, being in the same order of the finesse reported in the literature for high performance microring resonators fabricated using the same polymeric resin.

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Cros, Dominique. "Les whispering gallery modes des resonateurs dielectriques : application aux oscillateurs et combineurs de puissance millimetriques." Limoges, 1990. http://www.theses.fr/1990LIMO0108.

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L'objectif de ce travail a ete l'analyse, la conception, la realisation et le test d'oscillateurs et de combineurs de puissance pouvant fonctionner dans la bande millimetrique 90-100 ghz. L'absence d'analyseur de reseau dans cette bande de frequence, nous a tout d'abord conduit a la mise au point d'un banc de mesure manuel des caracteristiques des dispositifs millimetriques. Puis, les oscillateurs et les combineurs de puissance etant constitues par l'association d'un circuit actif et d'un circuit passif, nous nous sommes plus particulierement interesses a l'analyse de ces derniers. C'est ainsi qu'utilisant la methode numerique des elements finis, ont pu etre successivement definis les parametres electromagnetiques (frequence de resonance, repartition du champ) et electriques (schema equivalent) des circuits associant des lignes de transmission microstrip et des r. D. Excites sur leurs whispering gallery modes. Les modeles mis au point ont ensuite ete valides experimentalement a 100 ghz lors de la realisation et du test d'un oscillateur millimetrique a diode gunn delivrant 5 mw, et d'un combineur de puissance permettant d'additionner la puissance de sortie de trois sources independantes

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Shah, Suhani Kiran. "Modeling scattered intensity from microspheres in evanescent field." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2021.

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Özel, Bilal [Verfasser], Gustav [Gutachter] Schweiger, and Cemal [Gutachter] Esen. "Entwicklung eines faseroptischen Temperatursensors auf der Basis von Whispering Gallery Modes / Bilal Özel ; Gutachter: Gustav Schweiger, Cemal Esen." Bochum : Ruhr-Universität Bochum, 2017. http://d-nb.info/1137379987/34.

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Balakireva, Irina. "Nonlinear dynamics of Kerr optical frequency combs." Thesis, Besançon, 2015. http://www.theses.fr/2015BESA2043.

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La présente thèse est consacrée à l’étude des peignes optiques de Kerr dans les résonateurs àmodes de galerie, au sein desquels la lumière peut être excitée par pompage externe. L’effet Kerrexistant dans ces résonateurs engendre des modes latéraux équidistants (dans le domaine spectral)de part et d’autre du mode excité, c’est à dire un peigne de fréquence. Cette thèse est diviséeen trois chapitres. Le premier est dédié à l’introduction de la génération de ces peignes et leurapplications. Le deuxième chapitre présente l’analyse de l’équation de Lugiato-Lefever, décrivantde manière analytique le système, et conduit à la construction de deux diagrammes de bifurcationpour les dispersions normale et anomale. Ils sont tracés en fonction des deux seuls paramètresexpérimentalement contrôlables une fois le résonateur fabriqué : la puissance du laser et sondécalage de fréquence. Ces diagrammes indiquent les plages de paramètres pour lesquels une,deux, ou trois solutions existent ainsi que leur stabilité. Les simulations numériques renseignentle type exact de solution associée à chaque aire (notamment les solitons brillants et sombres, lesbreathers, les peignes optiques de Kerr de premier et deuxième ordre, et un régime chaotique) ; cesdiagrammes indiquent donc les paramètres du laser à choisir afin de générer la solution souhaitée.Le troisième chapitre est dédié aux peignes de Kerr optique secondaires, lignes additionnelles dansle domaine spectral générées entre les lignes du peigne principal. Ils apparaissent en dispersionanormale, lorsque la quantité de photon pompe excède un seuil dit de second ordre, qui a étédéterminé numériquement
This thesis is dedicated to the study of the Kerr optical frequency combs in whispering gallery moderesonators, where the light can be excited by the extern pump. Due to the Kerr effect existing in theseresonators, the quasi-equidistant lines in the spectral domain are generated around the excited mode,that is the frequency comb. This thesis is devided in three chapters. The first one is dedicated to theintroduction of the Kerr comb generation and their applications.The second one presents the analysisof the Lugiato-Lefever equation used for the analytical study of the system, leading to the constructionof two bifurcation diagrams for the normal and anomalous dispersions. They are plotted for twoparameters, which can be controlled during experiments once the resonator has been fabricated,which are the pump power of the laser and its frequency detuning. These diagrams show the areas ofthe parameters for which one, two, or three solutions exist and their stability. The additional numericalsimulations show the exact type of the solution in each area (such as the bright and dark solitons,the breathers, the primary and secondary Kerr combs and chaotical regimes), finally these diagramsshow the parameters of the laser needed to be choosen for the generation of the desired solution.The third chapter is dedicated to the secondary Kerr combs, which are the additional lines generatedbetween the lines of the primary comb. They appear in the anomalous dispersion regime, when thequantity of the pump photons crosses the second-order threshold, which has been found numerically

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Jager, Jean-Baptiste. "Fabrication et étude optique de microcavités à modes de galerie intégrées sur silicium." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENY017/document.

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Ce travail de thèse a consisté à mettre en place toute une filière de fabrication de microtores en silice sur silicium (étapes de lithographie et de gravure en salle blanche pour la réalisation de microdisques, installation d'un banc optique permettant la transformation du résonateur en microtore par un procédé de recuit laser CO2), à installer un banc optique permettant de mesurer la largeur spectrale de leurs résonances optiques à 1.55 µm et enfin, à explorer l'intégration d'émetteurs de lumière composés d'éléments de la colonne IV comme du silicium et du germanium, dans ces cavités. Des microtores supportant des résonances de facteur de qualité Q proche de 10^8 à 1.55 µm ont été fabriqués. Ces réalisations sont très proches de l'état de l'art et valident à la fois la fabrication des cavités et le banc optique permettant les mesures spectrales des modes de galerie (WGM). Grâce à un contrôle fin des différentes étapes de fabrication, de nouveaux résonateurs ont également été réalisés, des microsphères de silice sur puce de petits rayons (entre 5 et 14 µm). Une étude détaillée de ces résonateurs est présentée. Des Q proches de 10^8 ont également été mesurés. Des cavités WGM comportant une couche de nanoclusters de silicium dans une matrice de silice avec des ions erbium (SiOx : Er) sont étudiées en photoluminescence. Un couplage des ces émetteurs à des WGM est observé à température ambiante dans le visible et dans l'infrarouge. Un travail de couplage du germanium aux WGM a commencé et semble prometteur
This work consisted in developing a fabrication process of silica microtoroids on a silicon chip (steps of lithography and etching in clean room for the realization of microdisks, set up of an optical bench to form a microtoroid with a reflow treatment of a silica microdisk by a CO2-laser), setting up an optical bench to measure the linewidth of their optical resonances at 1.55 µm and finally, exploring light emitters integration in these cavities such as silicon and germanium. Very high quality-factors (Q) close to 10^8 at 1.55µm have been measured on microtoroids. These realizations are very close to the State of the art and validate both the fabrication of these cavities and the optical bench to measure the linewidth of their Whispering Gallery Modes (WGM). With a precise control of the fabrication steps, new resonators have also been fabricated, silica microspheres on a chip with small radii (5 < r < 14µm). An in-depth study of these last ones is presented. Q-factors close to 10^8 have also been measured on microspheres. WGM cavities with a SiOx: Er layer (silicon nanoclusters in silica with erbium ions) are studied by photoluminescence. Coupling of these light emitters to WGM is observed in visible and near infrared at room temperature. A work of coupling of germanium to WGM began and seems promising

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ARMAROLI, Andrea. "Modelling and Characterization of Guiding Micro-structured Devices for Integrated Optics." Doctoral thesis, Università degli studi di Ferrara, 2008. http://hdl.handle.net/11392/2389240.

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In this thesis we show several modelling tools which are used to study nonlinear photonic band-gap structures and microcavities. First of all a nonlinear CMT and BPM were implemented to test the propagation of spatial solitons in a periodic device, composed by an array of parallel straight waveguides. In addition to noteworthy theoretical considerations, active functionalities are possible by exploiting these nonlinear regimes. Another algorithm was developed for the three-dimensional modelling of photonic cavities with cylindrical symmetry, such as microdisks. This method is validated by comparison with FDTD. We also show the opportunity to confine a field in a region of low refractive index lying in the centre of a silicon microdisk. High Q-factor and small mode volumes are achieved. Finally the characterization of microdisks in SOI with Q-factor larger than 50000 is presented

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Hon, Kam Yan. "Surface plasmon resonance-assisted coupling to whispering-gallery modes in micropillar resonators and silicon microdisk-based depletion-type modulators using integrated schottky diodes /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?ECED%202007%20HON.

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Gorkowski, Kyle J. "The Morphology and Equilibration of Levitated Secondary Organic Particles Under Controlled Conditions." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1067.

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I advanced the understanding of particle morphology and its implications for the behavior and effects of atmospheric aerosol particles. I have developed new experimental methods for the Aerosol Optical Tweezers (AOT) system and expanded the AOT’s application into studying realistic secondary organic aerosol (SOA) particle phases. The AOT is a highly accurate system developed to study individual particles in real-time for prolonged periods of time. While previous AOT studies have focused on binary or ternary chemical systems, I have investigated complex SOA, and how they interact with other chemical phases, and the surrounding gas-phase. This work has led to new insights into liquid-liquid phase separation and the resulting particle morphology, the surface tension, solubility, and volatility of SOA, and diffusion coefficients of SOA phases. I designed a new aerosol optical tweezers chamber for delivering a uniformly mixed aerosol flow to the trapped droplet’s position. I used this chamber to determine the phase-separation morphology and resulting properties of complex mixed droplets. A series of experiments using simple compounds are presented to establish my ability to use the cavity enhanced Raman spectra to distinguish between homogenous single-phase, and phase-separated core-shell or partially-engulfed morphologies. I have developed a new algorithm for the analysis of whispering gallery modes (WGMs) present in the cavity enhanced Raman spectra retrieved from droplets trapped in the AOT. My algorithm improves the computational scaling when analyzing core-shell droplets (i.e. phase-separated or biphasic droplets) in the AOT, making it computationally practical to analyze spectra collected over many hours at a few Hz. I then demonstrate for the first time the capture and analysis of SOA on a droplet suspended in an AOT. I examined three initial chemical systems of aqueous NaCl, aqueous glycerol, and squalane at ~ 75% relative humidity. For each system I added α-pinene SOA – generated directly in the AOT chamber – to the trapped droplet. The resulting morphology was always observed to be a core of the initial droplet surrounded by a shell of the added SOA. By combining my AOT observations of particle morphology with results from SOA smog chamber experiments, I conclude that the α-pinene SOA shell creates no major diffusion limitations for water, glycerol, and squalane under humid conditions. My AOT experiments highlight the prominence of phase-separated core-shell morphologies for secondary organic aerosols interacting with a range of other chemical phases. The unique analytical capabilities of the aerosol optical tweezers provide a new approach for advancing the understanding of the chemical and physical evolution of complex atmospheric particulate matter, and the important environmental impacts of aerosols on atmospheric chemistry, air quality, human health, and climate change.

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Park, Young-Shin 1972. "Radiation pressure cooling of a silica optomechanical resonator." Thesis, University of Oregon, 2009. http://hdl.handle.net/1794/10559.

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xi, 125 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.
This dissertation presents experimental and theoretical studies of radiation pressure cooling in silica optomechanical microresonators where whispering gallery modes (WGMs) are coupled to thermal mechanical vibrations. In an optomechanical system, circulating optical fields couple to mechanical vibrations via radiation pressure, inducing Stokes and anti-Stokes scattering of photons. In analogy to laser cooling of trapped ions, the mechanical motion can in principle be cooled to its ground state via the anti-Stokes process in the resolved-sideband limit, in which the cavity photon lifetime far exceeds the mechanical oscillation period. Our optomechanical system is a slightly deformed silica microsphere (with a diameter 25-30 μm ), featuring extremely high Q -factors for both optical ( Q o ∼ 10 8 ) and mechanical ( Q m ∼ 10 4 ) systems. Exploiting the unique property of directional evanescent escape in the deformed resonator, we have developed a free-space configuration for the excitation of WGMs and for the interferometric detection of mechanical displacement, for which the part of input laser that is not coupled into the microsphere serves as a local oscillator. Measurement sensitivity better than 5 × 10 -18 m /[Special characters omitted.] has been achieved. The three optically active mechanical modes observed in the displacement power spectrum are well described by finite element analysis. Both radiation pressure cooling and parametric instabilities have been observed in our experiments. The dependence of the mechanical resonator frequency and linewidth on the detuning as well as the intensity of the input laser show excellent agreement with theoretical calculations with no adjustable parameters. The free-space excitation technique has enabled us to combine resolved sideband cooling with cryogenic cooling. At a cryogenic temperature of 1.4 K, the sideband cooling leads to an effective temperature as low as 210 m K for a 110 MHz mechanical oscillator, corresponding to an average phonon occupation of 37, which is one of the three lowest phonon occupations achieved thus far for optomechanical systems. The cooling process is limited by ultrasonic attenuation in fused silica, which should diminish when bath temperature is further lowered, with a 3 He cryostat, to a few hundred millikelvin. Our experimental studies thus indicate that we are tantalizingly close to realizing the ground-state cooling for the exploration of quantum effects in an otherwise macroscopic mechanical system.
Committee in charge: Michael Raymer, Chairperson, Physics; Jens Noeckel, Member, Physics; Hailin Wang, Member, Physics; Paul Csonka, Member, Physics; Jeffrey Cina, Outside Member, Chemistry

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Mialichi, José Roberto. "Ressonadores de microdiscos com região ativa nanoestruturada bombeados por injeção eletrônica." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/278523.

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Orientador: Newton Cesário Frateschi
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-08-17T02:03:42Z (GMT). No. of bitstreams: 1 Mialichi_JoseRoberto_D.pdf: 4426656 bytes, checksum: f54944bc3408b22608afdd373e3445dd (MD5) Previous issue date: 2010
Resumo: Esta tese de doutorado apresenta resultados experimentais do crescimento de pontos quânticos de InAs diretamente sobre InGaAsP de baixa energia de bandgap (?g=1420 nm), cujo desenvolvimento visa a obtenção de um meio ativo com emissão na banda C (1520¿1570 nm) para a fabricação de ressonadores de microdisco. Baseado em resultados de fotoluminescência e microscopia de força atômica, o fenômeno da inter-difusão de elementos na interface InAs/InGaAsP é proposto e calculado, indicando a presença de Gálio e Fósforo na composição dos pontos quânticos. O ganho óptico de pontos quânticos de InAs crescidos sobre InGaAsP é também calculado com base nos resultados obtidos na análise de inter-difusão. Subseqüentemente, a teoria dos modos ressonantes no microdisco, particularmente os modos chamados whispering gallery modes (WGMs), é desenvolvida com o intuito de auxiliar os cálculos de fator de qualidade, fator de confinamento e corrente de limiar. Uma estrutura multicamada (diodo PIN) com região ativa baseada em pontos quânticos do sistema InAs/InGaAsP foi crescida por epitaxia de feixe químico (CBE) para a fabricação de ressonadores de microdisco. A fabricação dos microdiscos é feita por litografia óptica, corrosão por plasma de íons e ataque químico seletivo de InP. Feixe de íons focalizados (FIB) foi usado para substituir o ataque por plasma para diminuir a rugosidade das paredes dos discos. Os ressonadores de microdiscos são caracterizados elétrica e opticamente e os resultados são confrontados com base nos resultados teóricos apresentados ao longo da tese. Com base nos resultados das caracterizações eletro/ópticas dos ressonadores, correções como a inclusão de perdas ópticas da rugosidade da borda e aquecimento local foram acrescidas ao modelo teórico, resultando em boa concordância com os resultados experimentais. Por fim, apresentamos o desenvolvimento de dispositivos híbridos a partir de polímeros orgânicos depositados diretamente sobre microdiscos de InGaAs com o objetivo de integrar meio ativo orgânico com ressonadores inorgânicos para aplicações em optoeletrônica. Estes resultados foram obtidos durante o programa de doutorado com estágio no exterior no Laboratório Nacional de Nanotecnologia (NNL) vinculado à Università del Salento (Lecce/Itália)
Abstract:This doctorate¿s thesis presents the growth of InAs quantum dots directly on high bandgap InGaAsP (?g=1420 nm) barriers to be used as the active region of microdisk resonators with emission in the C-band (1520¿1570 nm). Based on photoluminescence and atomic force microscopy experiments, the occurrence of inter-diffusion on the InAs/InGaAsP interface is calculated, suggesting the presence of Gallium and Phosphorus in the quantum dots (QDs) composition. Based also on the inter-diffusion results, the optical gain of the InAs QDs is calculated. Subsequently, microdisk resonator whispering gallery modes (WGMs) are calculated and employed to predicting the cavity quality and confinement factors, as well as the threshold current. A PIN diode with an active region based on InAs QDs was grown by Chemical Beam Epitaxy (CBE) for the fabrication of current injected microdisk resonators. Microdisk fabrication process is performed using photolithography, reactive ion etching and InP selective wet-etching. Focused ion beam is used to replace the plasma etching in order to reduce the roughness of the disk¿s edge. Microdisks resonators are characterized electrically and optically and the measurements are analyzed based on the theoretical results presented along this thesis. Based on these measurements, optical losses caused by disk¿s edge roughness and local heating are added to our simulation tool, resulting in better agreement with the experimental results. Finally, we present the development of hybrid resonators using organic polymer deposited directly on inorganic microdisks integrating an organic active medium with inorganic resonators for optoelectronic applications. These results were obtained during our work at the National Nanotechnology Laboratory (NNL) and the University of Salento (Lecce/Italy)
Doutorado
Física da Matéria Condensada
Doutor em Física

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Moore, Lee James. "Spectroscopy and dynamics of colloidal particles and systems at interfaces." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:80b11157-18d9-4262-9432-c7fe82e24213.

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This thesis presents an investigation of the dynamic properties of wide range of interfacial systems, from colloidal particles in solution, through the realm of aerosols and onto studies of molecular adsorption at an interface. The primary experimental technique utilized is optical tweezers. An exploration of the history of the use of radiation pressure to manipulate matter is presented, followed by an introduction to how optical tweezers work. Some of the more advanced methods of tweezing are discussed, with an emphasis on the use of spatial light modulators (SLMs) to realise dynamic holographic optical tweezers (DHOTs), an example of which has been constructed within our laboratory using off-the-shelf optical components, and combined with a spectrometer to facilitate high resolution spectroscopic studies of microscopic systems. The spectroscopic analysis of microparticles is greatly enhanced by optical feedback generated when the wavelength of light utilized is an integer number of wavelengths around the circumference of the microsphere. Enhanced signal occurs at these wavelengths, termed whispering gallery modes (WGMs). The absolute position of these resonances depends strongly upon the shape, size and refractive index of the particle, and is predicted by Mie theory. A discussion of the concepts behind Mie theory, as well as how to use an experimental WGM spectrum to deduce the size and composition of a microparticle, is provided. This technique is then put to use in a detailed study on the properties of single aerosols, comprised of sodium chloride solution, and generated using a handheld medical nebulizer. Studies have been carried out on both evaporating and growing droplets trapped with a Gaussian beam; in the latter case, periods of size stability are observed, owing to resonant absorption of radiation at the trapping laser wavelength. The SLM can be used to change the trapping laser to a Laguerre-Gaussian (LG) mode, and an investigation of how this affects the dynamics of the droplet is presented. It is found that the use of LG modes with $ellgeq10$ produced Raman spectra with significantly more intense WGMs, and also suppressed droplet evaporation. Through observations made with fluorescent polystyrene microspheres, it is argued that the LG modes are more efficient at coupling into WGMs of the droplets. Leading on from these experiments on salt water droplets, experiments have been conducted using ionic liquids (ILs). These fluids have many fascinating properties and potential applications. The optical trapping of droplets comprised of aqueous solutions of the ionic liquid ethylammonium nitrate (EAN) and water has been demonstrated for the first time. These droplets are analysed spectroscopically by illuminating them with the output from a broadband LED; WGMs that are observed in the backscattered light are used to determine their size and composition. The response of the droplets to conditions of varying relative humidity has also been investigated. In order to characterise the relative humidity experienced by both the salt water and IL droplets, the concentration of water vapour within the trapping cells has been measured using diode laser absorption spectroscopy. The spatially modulated laser beam is then utilized in a different fashion; instead of optically tweezing a sample, a low numerical aperture objective lens is utilized to focus the laser onto the surface of a gold coated microscope slide. When a colloidal sample is placed on this surface, the thermal gradients cause the particles to form two dimensional crystals. The SLM is utilized to form multiple nucleation sites, and the dynamics of the crystals are directly observed in real time using video microscopy. It is found that grain rotation-induced grain coalescence (GRIGC) occurs, with the rotation of both crystals before coalescence. Control over the grain size is achieved by altering the separation of the laser spots, and shows that the time scale for grain boundary annealing in our system is in good agreement with theoretical expressions formulated for nanocrystal growth. Finally, as a complimentary technique to the microparticle spectroscopy previously discussed, a bulk interface is probed by using evanescent wave broadband cavity enhanced absorption spectroscopy (EW-BBCEAS) specifically to study the adsorption of cytochrome c (cyt c) to a fused silica surface. Visible radiation from a supercontinuum source is coupled into an optical cavity consisting of a pair of broadband high reflectivity mirrors, and a total internal reflection (TIR) event at the prism/water interface. Aqueous solutions of cyt c are placed onto the TIR footprint on the prism surface and the subsequent protein adsorption is probed by the resulting evanescent wave. The time integrated cavity output is directed into a spectrometer, where it is dispersed and analysed. The broadband nature of the source allows observation of a wide spectral range (ca 250 nm in the visible). The system is calibrated by measuring the absorption spectra of dyes of a known absorbance. Absorption spectra of cyt c are obtained for both S and P polarized radiation, allowing information about the orientation of the adsorbed protein to be extracted.

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Du, Xuan. "Mode-Matching Analysis of Whispering-Gallery-Mode Cavities." Thesis, 2013. http://hdl.handle.net/1828/5113.

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This thesis presents a full-vectorial mode matching method for whispering gallery microcavity analysis. With this technique, optical properties such as resonance wavelength, quality factor and electromagnetic field distribution of an arbitrarily shaped microcavity can be computed with high accuracy. To illustrate this, a mode matching analysis that involves a single propagating whispering gallery mode is performed on a microtoroid in the presence of individual nonplasmonic nanoparticle on its surface. This method is also extended to the analysis of cavity adsorbed by a plasmonic nanoparticle at a wavelength close to plasmon resonance where the resulting field distortion invalidates other approaches. The simulation demonstrates high efficiency and is in close agreement with experimental measurements reported in previous work. Furthermore, we extend our mode matching analysis to the case where multiple whispering gallery modes are involved in the course of light propagation. The new formalism is performed on a cavity-waveguide coupling system to investigate the light delivery from a tapered optical waveguide to a microcavity at high precision. A novel hybrid integration scheme to implement an ultra-high quality factor microcavity on a silicon-on-insulator platform is proposed based on the related modelling results.
Graduate
0752
0544
duxuanmax@gmail.com

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Yu, Wenyan. "Enhanced high Q whispering gallery resonator sensing." Thesis, 2012. http://hdl.handle.net/1828/4152.

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This thesis presents a novel method to fabricate metallic nanostructures on whispering gallery mode (WGM) cavity surfaces. The unique properties of WGM cavities have shown their promising future in both fundamental research and engineering applications. High sensitivity biosensors are one of the most important applications. Thanks to their ultra high quality factor (Q) and small optical mode volume, the resonant frequency shift of a single nanoparticle binding becomes detectable. The basic principles of a WGM cavity and its coupling mechanism with an optical coupler are discussed in detail. From the WGM sensing principle, people have demonstrated the positive contributions of the surface plasmon to the sensitivity. Furthermore, we implement the localized surface plasmon resonance (LSPR) on the cavity surface by depositing metallic dots. We use the focused ion beam (FIB) to directly deposit metallic nanodots on the spherical cavity surface for the first time. The quality factor of the cavity with metallic dots is above 10^7 in both air and water, which is more than one order larger than other published results. Also, the new method is much more controllable and repeatable than previous methods. It reveals a new fabrication method for potential ultra sensitive sensors based on WGM cavities. In addition, we offer a new mode solver for the toroidal WGM cavity. The microtoroid is a better platform for further investigation of WGM sensing than the microsphere. By expanding cavity modes to a set of normal fiber modes, we formulate the new mode solver based on simple physical principles. The simulation results of the radiative quality factor based on the new mode solver are presented as well.
Graduate

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"Optical whispering gallery mode resonances in asymmetric morphologies." UNIVERSITY OF CALIFORNIA, LOS ANGELES, 2008. http://pqdtopen.proquest.com/#viewpdf?dispub=3272250.

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Vincent, Serge M. "Full-Vector Finite Difference Mode Solver for Whispering-Gallery Resonators." Thesis, 2015. http://hdl.handle.net/1828/6630.

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Optical whispering-gallery mode (WGM) cavities, which exhibit extraordinary spatial and temporal confinement of light, are one of the leading transducers for examining molecular recognition at low particle counts. With the advent of hybrid photonic-plasmonic and increasingly sophisticated forms of these resonators, the importance of supporting numerical methods has correspondingly become evident. In response, we adopt a full-vector finite difference approximation in order to solve for WGM's in terms of their field distributions, resonant wavelengths, and quality factors in the context of naturally discontinuous permittivity structure. A segmented Taylor series and alignment/rotation operator are utilized at such singularities in conjunction with arbitrarily spaced grid points. Simulations for microtoroids, with and without dielectric nanobeads, and plasmonic microdisks are demonstrated for short computation times and shown to be in agreement with data in the literature. Constricted surface plasmon polariton (SPP) WGM's are also featured within this document. The module of this thesis is devised as a keystone for composite WGM models that may guide experiments in the field.
Graduate

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Tzu-YangChao and 趙子揚. "Exciton-polariton lasing properties of ZnO whispering gallery mode microcavity." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/43653947055386468504.

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碩士
國立成功大學
光電科學與工程學系
102
We demonstrate the effects of exciton-polariton in a ZnO microcavity investigated by angle-resolved micro-photoluminescence spectroscopy at room temperature. The one-dimensional hexagonal ZnO microcavities synthesized by vapor phase transport method provide an optical cavity of whispering gallery modes (WGMs) and laser gain medium as well. The photon propagates in the hexagonal cross section plane as a result of multiple total internal reflections at the ZnO/air interface. Therefore, the exciton of ZnO strongly coupled to the WGM can form exciton-polariton. The polariton presents the anticrossing behavior in energy momentum diagram showing the strong interaction between exciton and cavity photon existed inside the ZnO microcavity under low carrier density excitation. Upon pulse laser pumping, we observe lasing action of the emission peaks and the blueshift of the polariton modes. An exciton-polariton condensation is also observed at room temperature throughout the power-dependent angle-resolve photoluminescence spectra.

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Peebles, Robb Allan. "Whispering-gallery mode generation using an azimuthal array of apertures." 1992. http://catalog.hathitrust.org/api/volumes/oclc/32449526.html.

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Thesis (M.S.)--University of Wisconsin--Madison, 1992.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 119-120).

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Huang, Yi-Chia, and 黃翊嘉. "Whispering-gallery mode of Phononic Crystal affect Surface Acoustic Wave." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/m6qpvz.

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Grudinin, Ivan Sergeevich. "Crystalline Whispering Gallery Mode Resonators for Quantum and Nonlinear Optics." Thesis, 2008. https://thesis.library.caltech.edu/5186/1/Grudinin.pdf.

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This work describes a series of projects and technology developments aimed at the realization of a solid-state photonic-ionic trap for quantum optics experiments. The projects however, are not constrained to this goal and explore the fields of nonlinear optics and fabrication techniques.

Fabri-Perot resonators have transformed the optical technology and can be found in many devices that utilize laser radiation. Whispering gallery mode resonators (WGMR) are relatively new elements and have such advantages as compactness, highest optical quality factors, and relative ease of fabrication. Small optical mode volume and long storage times allow record low thresholds of various nonlinear processes. Raman and Brillouin lasing, second and third harmonic generation, parametric oscillations and four wave mixing have all been enhanced in WGM resonators. Compared to glass microspheres, crystalline WGM resonators have higher nonlinear coefficients, may not be sensitive to water vapor, and have generally higher purity leading to record optical quality (Q) factors. Zero phonon lines of ions in crystals enable applications in cavity QED with single ions.

A novel application of diamond turning to fabrication of axially symmetric crystalline optical resonators is described. This technique enabled crystalline WGM microresonators, multiple resonators coupled via the evanescent field, and a single mode resonator. Crystalline resonators having a record high optical Q of 10¹¹ were demonstrated. Fundamental limits of the Q factor were investigated and Q=10¹⁵ was predicted at cryogenic temperatures. Record low threshold and high efficiency of stimulated Raman and Brillouin scattering led to the first observations of these effects in crystalline cavities. Brillouin and Raman lasers based on WGM resonators are expected to have very narrow linewidth. A cryogenic setup was developed that allowed observation of WG modes at low temperatures. Crystalline cavity was used as a reference for narrowing a linewidth of a commercial diode laser with a Pound-Drever-Hall technique for the first time. A device based on a fused silica WGMR was used to generate beams with large angular momenta. In addition, a Fabri-Perot cavity was used to sense thermal expansion of mirrors to derive thermal expansion and temperature conductivity of thin optical coatings.

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Sprenger, Benjamin [Verfasser]. "Stabilizing lasers using whispering gallery mode resonators / vorgelegt von Benjamin Sprenger." 2010. http://d-nb.info/1009147056/34.

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Dissertations / Theses on the topic 'Whispering gallery mode'

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