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1
Maker, Gareth Thomas. "Diode laser pumped solid state lasers." Thesis, University of Southampton, 1990. https://eprints.soton.ac.uk/397281/.
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This thesis deals with the development of diode laser pumped solid state lasers. The earliest work presented enabled 125W peak power, single frequency Q-switched pulses to be obtained from a 100mW diode laser pumped Nd:YAG laser. Using a 500mW diode laser as a pump source for C.W. Nd:YAG and Nd:YLF oscillators an Yb:Er fibre laser was pumped, producing 0.75mW C.W. power at a wavelength of 1.56µm. Acousto-optic mode-locking techniques were used to provide C.W. mode-locked pulse durations in Nd:YAG and Nd:YLF of 55ps and 18ps respectively, at repetition rates of 240MHz. Frequency modulation mode-locking was shown to be a superior technique, giving pulse durations of 11.5ps and 10ps in diode laser pumped Nd:YAG and Nd:YLF oscillators respectively. FM operation of diode laser pumped Nd:YAG lasers was investigated, yielding a maximum FM bandwidth of 70GHz. Spatial hole burning was considered to be an important factor in this result. Using a 1W diode laser to pump a mode-locked and Q-switched Nd:YLF oscillator peak power levels of 70kW were obtained at a wavelength of 1.047µm. Frequency doubling this output in MgO:LiNbO3 with an energy conversion efficiency of 47% enabled other tunable lasers to be pumped using the second harmonic. Firstly, a synchronously pumped rhodamine 6G dye laser is described which is capable of producing 3.2ps mode-locked pulses in a Q-switched envelope with peak powers of around 10kW. Secondly, a synchronously pumped doubly resonant optical parametric oscillator tunable between 983nm and 1119nm is described. Lastly, a Ti:Sapphire laser producing 400ns pulses with peak powers of 3W at a wavelength of 755nm is demonstrated. This oscillator could be wavelength tuned between 746nm and 838nm. A highly efficient method of frequency doubling C.W. mode-locked lasers was developed. Using an external resonant cavity a frequency doubling energy conversion efficiency of 61% to 532nm was achieved, giving 87mW average power in 8.5ps pulses.
2
Gallaher, Nigel R. "Narrow linewidth, diode laser pumped, solid state lasers." Thesis, University of St Andrews, 1994. http://hdl.handle.net/10023/13717.
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The design, construction, evaluation and development of an all solid state, narrow linewidth laser source is presented. The narrow linewidth laser system was based on a miniature standing wave Nd:YAG laser cavity, end-pumped with 100mW of 809nm light from a fibre coupled GaAlAs diode laser array. This basic CW laser generated up to 30mW at 1064nm in a single, diffraction limited transverse mode (TEM00) but multi-longitudinal mode output beam. The laser had a pump power threshold of 24mW and an optical to optical slope efficiency of 39%. A simple rate equation based numerical model of this laser was developed to allow various design parameters such as length of Nd:YAG gain medium and amount of output coupling to be optimised. Excellent agreement between the numerical model predictions of the output power as a function of input pump power and experimental data from the optimised multi-longitudinal mode laser was obtained. To restrict this laser to operate on a single longitudinal mode, twisted cavity mode and intracavity etalon, mode selecting techniques were investigated. Both methods were found to produce reliable single mode laser operation and resulted in output powers at the 10mW level. The relative free running frequency stability between a pair of single longitudinal mode diode laser pumped Nd:YAG lasers was investigated. By isolating these lasers from environmental noise using a small, custom built anechoic chamber the linewidth of the optical heterodyne signal between the two free running lasers was reduced from tens of megahertz to around 10kHz measured on a millisecond time scale. Further improvement in linewidth was achieved by actively locking the laser frequency to a novel ultra high finesse (F~12,500, free spectral range ~500MHz) spherical mirror Fabry-Perot reference interferometer using the technique of Pound-Drever locking. The locked laser displayed a maximum frequency deviation of only 1kHz from the centre of the reference cavity transmission and a frequency noise spectral density of ~20Hz/ √Hz at 1kHz. In one of the first reported demonstrations of an all solid state injection seeded laser system, this single frequency laser was used to injection seed a diode laser array, transversely pumped, Q-switched Nd:YAG laser to produce 0.25mJ, 35ns pulses in a single longitudinal, single transverse mode beam. Preliminary results on injection locking between two single frequency diode laser pumped Nd:YAG laser are also reported. A novel frequency stabilisation scheme based on resonant optical feedback locking iproposed and some preliminary experimental work on this technique is presented.
3
Scourfield, Gareth D. "Turnable, infrared, solid-state lasers." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318632.
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Spiekermann, Stefan. "Compact diode-pumped solid-state lasers." Doctoral thesis, KTH, Physics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3772.
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Compact diode-pumped solid-state lasers (DPSSL) arecontinuously replacing traditional gas lasers as well asenabling completely new technology. However, compact and costefficient designs are required to satisfy end-user demands. Theaim of this thesis was therefore to investigate novel laserdesigns for given applications considering these demands. In alarge part of the thesis work, nonlinear optics were employedto realize laser wavelengths where there was no appropriatelaser transition available.
Besides other nonlinear crystals such as BBO, LBO and KTP,periodically poled KTP played an important role in this thesiswork. Its unique properties regarding up conversion processeswere exploited, thus supplying a broadened view over itspotential and limitations.
This thesis places emphasis on practical concerns, mainlyrelated to real applications. It gives solutions to the beamshaping of laser diodes, covers the simulation and the designof laser dynamics as well as laser performance and describesthe sources of laser output degradation and damage mechanisms.Novel infrared lasers were designed and multiple intra-cavity,external cavity and non-resonant multi-pass frequencyconversion schemes were successfully employed and optimized.These produced red, orange, green, blue and ultraviolet outputfor various applications like spectroscopy, micro machining andwriting of fiber Bragg gratings.
Keywords:diode-pumped solid-state lasers, nonlinearoptics, frequency conversion,
5
Hellström, Jonas. "On diode-pumped solid-state lasers." Doctoral thesis, KTH, Tillämpad fysik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4580.
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The research that is presented in this thesis can be divided into two major parts. The first part concerns longitudinally pumped, bulk Er-Yb lasers. In these lasers, the main limitation is the thermal shortcomings of the phosphate glass host material. From the laser experiments and the spectroscopic measurements on crystalline host materials, as well as an investigation to bring further light to the physical background of the involved dynamics, the thesis presents some novel results that contribute to the search for a crystalline replacement. The second part concerns novel laser concepts applied to Yb-doped double tungstate lasers. Different crystal orientations are investigated, such as an athermal orientation for reduced thermal lensing and a conical refraction orientation for complete polarization tuning. Furthermore, the introduction of volume Bragg gratings in the cavity enables wide spectral tuning ranges and extremely low quantum defects. Regarding the first part, the main results are the achievement of 15 % slope efficiency in a monolithic, continuous-wave Yb:GdCOB laser and the achievement of Q-switching of the same laser. The Q-switched pulse durations were around 5-6 ns and the Q-switched slope efficiency was 11.6 %. For both lasers, a maximum output power of 90 mW was obtained, which is close to ordinary glass lasers under similar conditions. A spectroscopic investigation into the Er,Yb-codoped double tungstates was also performed and the results have enabled mathematical modeling of the fluorescence dynamics in these materials. Finally, the temperature dependence of the dynamics in Er,Yb:YAG was studied and the results have given some insight into the physical background of the mechanisms involved. Regarding the second part, different end-pumped Yb:KReW laser cavities were constructed to demonstrate the different concepts. With a laser crystal cut for propagation along the athermal direction at 17º angle clockwise from the dielectric direction Nm, the thermal lens could be reduced by 50 %. In these experiments the maximum output power was 4 W at 60 % slope efficiency. In another cavity incorporating a volume Bragg grating in a retroreflector set-up, the wavelength could be continuously tuned between 997 - 1050 nm. The spectral bandwidth was 10 GHz and the peak output power was 3 W. The same output power could also be obtained at 1063 nm with the grating positioned as an output coupler instead. If, on the other hand, the grating was positioned as an input coupler, 3.6 W output power at 998 nm was obtained at a quantum defect of only 1.6 %. Furthermore, using a crystal oriented for propagation along an optic axis, internal conical refraction could be used to establish arbitrary control of the polarization direction as well as the extinction ratio. Even unpolarized light could be enforced despite the highly anisotropic medium. With this configuration, the maximum output power was 8.6 W at 60 % slope efficiency which equals the performance of a reference crystal with standard orientation. The completely novel concepts of laser tuning with Bragg grating retroreflectors, of low quantum defect through Bragg grating input couplers and of polarization tuning by internal conical refraction can all easily be applied to several other laser materials as well.QC 20100713
6
Conroy, Richard. "Microchip lasers." Thesis, St Andrews, 1998. http://hdl.handle.net/10023/531.
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Thornburg, Kennerly Scott Jr. "Synchronization of coupled solid-state lasers." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/30889.
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Rabeendran, Nishanthan. "New Approaches to Gyroscopic Lasers." Thesis, University of Canterbury. Physics and Astronomy, 2013. http://hdl.handle.net/10092/8609.
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This thesis presents a study of two aspects of ring laser gyroscopes: Correction of systematic errors due to optical backscatter, and development of solid-state ring laser gyroscopes.
Backscatter at the optical surfaces of ring laser gyroscopes causes systematic measurement errors. These errors were modelled and corrected for in large ring lasers. The model included backscattering, hole burning and dispersion in the gain medium. The model predictions were used in conjunction with measurements of
the intensity modulation of each beam and the phase difference between these modulation to correct the measured Sagnac frequency of the large ring lasers, PR-1 and G-0. Dramatic improvements in the sensitivity of both lasers were achieved.
Most current laser gyroscopes use He-Ne plasma as the gain medium. This makes the devices fragile, the plasma creates UV light that degrades the cavity mirrors and the gas itself degrades over time. As a alternative, solid state materials might be used as the gain medium for the gyroscope. Both neodymium doped and erbium ytterbium co-doped phosphate glass lasers were constructed. Initially linear cavity designs were constructed to test the suitability of the gain media. Both laser systems employed longitudinal laser diode pumping. Thirty six perimeter ring lasers were then developed using both gain media. In both cases successful rotation sensing was achieved on a turntable which provided external rotation. For rotation rates between 0.1 and 0.85 rad/s, the gyroscope built using Er-Yb and Nd phosphate glass are superior to Nd:YAG (the only other material known to have been used in a continuous wave solid state gyroscope). This improvement is due to the use of thin heavily doped gain medium, which decreases the detrimental effect caused by gain gratings.
9
Esser, M. J. Daniel. "Diode-end-pumped solid-state lasers." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1020.
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Hellström, Jonas. "On diode-pumped solid-state lasers /." Stockholm : Tillämpad fysik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4580.
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11
Thompson, Benjamin Aubrey. "Novel diode-pumped solid-state lasers." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416626.
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Li, Ran. "Advanced controllable solid-state Raman lasers." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26900.
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This thesis presents work on developing advanced controllable continuous-wave (CW) solid-state Raman lasers operating at near-infrared and visible wavelengths for astronomy and medical applications. An adaptive-optics (AO) technique, which is commonly applied in astronomy, was for the first time integrated within self-Raman lasers for improving the Raman laser output performances and wavelengths control. Over the last decade, intracavity solid-state Raman lasers have been widely utilised to extend the spectral coverage of common crystalline laser materials, especially when they are combined with second harmonic generation or sum frequency generation. However, due to the non-elastic nature of stimulated Raman scattering, a significant thermal lensing is generated within the Raman gain medium, which results in parasitic thermo-optical distortions inside the cavity. The magnitude of this effect scales directly with the Raman laser output power and has been identified as the main limitation in power-scaling crystalline Raman lasers. In this thesis, an AO-based feedback control loop system, consisting of an intracavity bimorph deformable mirror, a photodiode sensor and a PC-based control program using a random-search algorithm, has been implemented inside several Raman laser platforms demonstrating its potential for Raman laser output power-scaling. A power improvement of up to ~ 45 % is reported for a Nd:YVO4 self-Raman laser at λ = 1176 nm using an intracavity AO optimisation. Moreover, a frequency-doubled Nd:GdVO4 self-Raman laser in the yellow waveband (λ = 586.5 nm) has also been power-scaled using the intracavity AO technique, achieving a total power enhancement of ~ 41 %. These represent the potential to significantly alleviate the detrimental thermal lens effect and open avenues which will enable solid-state Raman lasers to reach new output power levels. In addition, several CW Nd:YVO4 self-Raman lasers based on the primary and secondary Raman shifts of YVO4 ( 893 cmˉ¹ and 379 cmˉ¹ respectively) were characterised and reported in this thesis. For the first time an on demand wavelengths selection between laser output at λ = 1109 nm and λ = 1176 nm has been achieved with hundreds of milliwatts output power using an intracavity AO control technique. This represents an important step on the way towards automatic wavelength selectable high power Raman lasers.
13
Goossens, Mark. "Ultrafast organic lasers and solid-state amplifiers." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/315.
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Mellish, Robert. "Ultrafast and all-solid-state Cr:LiSAF lasers." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243457.
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Liu, Yi-Wei. "Optical studies using tunable solid state lasers." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299523.
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Esser, M. J. Daniel. "Mid-infrared diode-pumped solid-state lasers." Thesis, Heriot-Watt University, 2010. http://hdl.handle.net/10399/2612.
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The concept of a diode-end-pumped Tm3+ laser pumping a Ho3+ laser was utilised to develop mid-infrared solid-state laser devices. After presenting an in-depth literature study of the promising material Tm:GdVO4, it was theoretically predicted and experimentally verified that a diode-end-pumped Tm:GdVO4 laser can be operated over a 100 nm wavelength range merely through the appropriate selection of the resonator output coupling value. The output at 1818 nm is the shortest wavelength demonstrated for a multi-watt Tm:GdVO4 laser, while the quasi-continuous-wave output power of 8.7 W at 1915 nm is the highest reported for a diode-end-pumped Tm:GdVO4 laser. A dual-end-pumped Tm:GdVO4 laser operating at 1892 nm was subsequently designed as pump source for a Ho:YLF laser, the implementation of which was demonstrated for the first time. The Q-switched Ho:YLF laser, pumped with a 83 mJ quasi-continuous-wave pulse of 19 ms duration at 5 Hz repetition rate, produced 1.9 mJ in a 17.6 ns pulse at 2051 nm on the π-polarisation, and 2.1 mJ in a 47.7 ns pulse on the σ-polarisation. This initial research work directed the way towards the development of high-energy Ho3+ lasers and amplifiers pumped with alternative high average power Tm3+ laser devices.
17
Paye, Malini. "Femtosecond pulse generation in solid-state lasers." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/38019.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (leaves 181-193).
by Malini Paye.
Ph.D.
18
Yoon, Sung Jin. "Cryogenically-cooled neodymium-doped solid-state lasers." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/415952/.
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The central idea of this thesis is to study cryogenically-cooled neodymium (Nd3+) doped lasers operating on the 4F3/2 → 4I9/2 transition around 0.95 microns, known as a quasi-four-level (QFL) transition. The QFL transition has unavoidable reabsorption loss at room temperature that introduces additional saturable losses into the laser cavity and must be overcome to achieve efficient operation. In general, this particular transition has lower gain than the dominant four-level 4F3/2 → 4I11/2 transition, around 1 micron. While the advantages of cryogenically cooled gain media have been recognised since the birth of the laser, in more recent times there has been a trend in exploiting these advantages for power-scaling QFL lasers, such as Yb-doped gain media. The first part of the thesis explores the extensive characterization of the spectroscopic properties of Nd3+ doped crystals. The present work tracks the spectroscopic changes over the temperature range from 77K to 450K. A number of crystals (YAG, GSAG, YVO4, GdVO4, KGW, YLF) hosting Nd3+ ions have been studied. The absorption cross section spectra for 800nm and 870nm bands were determined with 0.1nm resolution. The absorbance was measured exploiting the Beer-Lambert law and a bespoke set-up using two separate broadband light sources. The fluorescence spectrum was collected and characterized for the transitions to 4I9/2, 4I11/2, and 4I13/2 energy-levels from the metastable level, 4F3/2, from which we calculated the stimulated emission cross section of the various crystals and over the temperature range by applying the Füchtbauer-Ladenburg equation, with the measured fluorescence lifetime. Furthermore, in this report we determine the energy transfer upconversion parameters, for the same set of crystals, using the Z-scan technique. The technique measures the change in transmittance of a probe beam tuned to an absorption peak of crystal sample. The measured transmitted power changes as the intensity incident on the crystal is varied via scanning the beam size and correlated to the saturation intensity through a spatially-dependent rate equation model, we found excellent fit between experiment and simulation. The second part of this thesis reports the development of cryogenic lasers. The design strategies are described by end-pumped and side-pumped systems, with two different crystal geometries reported. Conventional radially-cooled rods are first reported with an end-pumping arrangement, then with a slab (Brewster angled, and afterwards AR coated), and finally a side-pumped Zigzag slab configuration. A rod geometry is tested using a Nd:YAG and a Nd:GSAG crystal for generation of QFL laser emission. The first end-pumped Nd:YAG rod have demonstrated 3.8W at 946nm for 12.8W of pump being absorbed and slope efficiency of 47%. Similar experiment was duplicated with Nd:GSAG rod demonstrating 3.5W at 942nm for 10.5W of pump absorbed. Both suffered significant modal instability during laser oscillation, which afterwards for the Nd:GSAG crystal was found to be due to AR-coating damage. A Nd:YAG slab crystal was tested for the both pumping configurations, using a wavelength-locked 869nm diode bar as a pump source. For this in-band pump-source, the quantum defect is only 8%, in the case of the main QFL transition. A top/bottom-face cooled slab presented effective mitigation of the previously observed modal stability, assumed to be associated with reducing birefringence losses. Despite the coating damage/contamination, which was repeatedly encountered, 946nm emission for both configurations was demonstrated. An end-pumping configuration has demonstrated 5.5W for 13.6W of absorbed pump with 47% slope efficiency. While the side-pumping the zigzag slab produced 6.3W for 30W of absorbed pump with 30% slope efficiency. It is expected that with improvements in the cleanliness within the vacuum chamber used for the cryogenic setup, better results in terms of slope efficiency, output power and beam quality will be realised in the near future.
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Bollig, Christoph. "Single-frequency diode-pumped solid-state lasers." Thesis, University of Southampton, 1997. https://eprints.soton.ac.uk/378587/.
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The work discussed in this thesis covers two broad areas: Novel techniques for the single-frequency operation of miniature, diode-pumped solid-state lasers and the high-power (i.e. multi-watt) operation of diode-bar end-pumped lasers in the eyesafe 2 μm wavelength region. A monolithic Nd-doped phosphate glass laser is described, in which uni-directional, hence single-frequency operation is enforced by the acousto-optic effect in the laser medium. The loss difference for the two counter-propagating waves relies on an acousto-optic self-feedback mechanism which can yield high loss differences even for very small diffraction efficiencies. Reliable single-frequency output is maintained indefinitely with an applied radio-frequency power of 0.2 W. Single-frequency output powers up to 30 mW for 400 mW of pump power are demonstrated. A technique is developed which facilitates reliable single-frequency operation of actively Q-switched lasers at repetition rates beyond the inverse lifetime of the upper laser level. Stable single-frequency operation of a Q-switched laser requires the initial establishment of a stable prelase which is free from spiking. Relying on the natural decay of spiking limits repetition rates and hence average power. Using feedback suppression of spiking, a Q-switched Nd:YAG laser is demonstrated which operates on a single frequency at repetition rates up to 25 kHz, with 88% of available cw power extracted. In the second part of this thesis, the high-power operation of diode-bar end-pumped solid-state lasers operating in the eyesafe 2 μm wavelength region is discussed. Efficient operation of a Tm:YAG laser end-pumped by a beam-shaped 20W diode bar is demonstrated. At a mount temperature of 20°C an output beam of 4.1 W with M2 values of 1.2 and 1.4 in the orthogonal planes is obtained for 13.5 W of diode power incident on the rod. This laser is then used to intracavity-pump a Ho:YAG laser, which avoids the upconversion problems usually associated with Tm3+-Ho3+-codoped lasers. At a mount temperature of 10°C for both the Tm:YAG and the Ho:YAG rods, an output power of the Ho:YAG of up to 2.1 W at 2097 nm is obtained for 9.2 W of diode power incident on the Tm:YAG rod.
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Elder, Ian F. "Diode-pumped two micron solid-state lasers." Thesis, University of Strathclyde, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284812.
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De, Syamsundar. "Noise in dual-frequency semiconductor and solid-state lasers." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112114/document.
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Les sources cohérentes de lumière émettant deux fréquences optiques avec une différence largement accordable dans le domaine radiofréquence et un fort degré de corrélation entre leurs fluctuations respectives peuvent être d’un grand intérêt pour de nombreuses applications telles que la photonique micro-onde, les horloges atomiques ultra stables, la physique atomique, la métrologie, etc. C’est le cas des lasers bifréquences émettant deux modes de polarisations linéaires croisées avec une différence de fréquence dans le domaine radiofréquence. Nous comparons les caractéristiques de telles sources bifréquences basées sur des lasers à semiconducteurs (VECSEL: vertical-external-cavity surface-emitting laser) ou des lasers à solide (notamment les solides dopés Nd3+ ou Er3+). Au-delà de la différence évidente entre les mécanismes de gain dans les lasers à semiconducteurs et dans les lasers à solide, le VECSEL bifréquence et le laser Nd:YAG bifréquence ne présentent pas la même dynamique. Le VECSEL bifréquence, comme pour un laser de classe A, a une dynamique dénuée d’oscillations de relaxation puisque la durée de vie des photons dans la cavité est beaucoup plus longue que celle de l’inversion de population. A l’opposé, le laser Nd:YAG bifréquence possède une dynamique présentant des oscillations de relaxation comme pour un laser de classe B, en vertu du fait que la durée de vie des photons dans la cavité est plus courte que celle de l’inversion de population. Dans cette thèse, nous explorons les mécanismes par lesquels cette dynamique, en plus du couplage non linéaire entre les deux modes, gouverne le bruit dans les lasers bifréquences. En particulier, nous analysons à la fois expérimentalement et théoriquement les propriétés spectrales des différents bruits (intensité, phase) ainsi que leurs corrélations dans le cas d’un VECSEL bifréquence de classe A et d’un laser Nd:YAG bifréquence de classe B. Enfin, un modèle de réponse linéaire de deux oscillateurs amortis couplés permet d’interpréter les résultats obtenus sur la corrélation entre ces différents bruitsCoherent sources emitting two optical frequencies with a widely tunable frequency difference lying in the radio-frequency range and having a high degree of correlation between their fluctuations can be useful for numerous applications such as microwave photonics, ultra-stable atomic clocks, atom manipulation and probing, metrology, etc. Dual-frequency lasers, which emit two orthogonal linearly polarized modes with a frequency difference lying in the radio-frequency range, have huge potentials for the above mentioned applications. We compare the characteristics of such dual-frequency oscillation in lasers based on either semiconductor (VECSEL: vertical-external-cavity surface-emitting laser) or solid-state active media (mainly Nd3+, or Er3+ doped crystalline host). Apart from the obvious difference between the gain mechanisms in semiconductor and solid-state laser media, the dual-frequency VECSEL and the dual-frequency Nd:YAG laser exhibit different dynamical behaviors. The dual-frequency VECSELs exhibit relaxation oscillation free class-A dynamics as the photon lifetime inside the cavity is longer than the population inversion lifetime. On the contrary, the dual-frequency Nd:YAG lasers obey class-B dynamics linked with the fact that the photon lifetime inside the cavity is shorter than the population inversion lifetime, leading to the existence of relaxation oscillations. In this thesis, we figure out how the laser dynamics, in addition to the nonlinear coupling between the two laser modes, governs different noise phenomena in dual-frequency lasers. In particular, we demonstrate, both experimentally and theoretically, the influence of the laser dynamics and the nonlinear coupling between the two modes on the laser noise, by analyzing the spectral properties of the different noises (intensity, phase) and their correlation in a class-A dual-frequency VECSEL (vertical-external-cavity surface emitting laser) and a class-B dual-frequency Nd:YAG laser. Moreover, the noise correlation results are interpreted in terms of the linear response of two coupled damped oscillators
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SOUSA, EDUARDO C. "Otimização da eficiência do modo TEMsub(oo) em lasers de Nd:LF de alta potência bombeados lateralmente." reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11720.
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Made available in DSpace on 2014-10-09T12:55:05Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:07:12Z (GMT). No. of bitstreams: 0
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:06/52787-0
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Serres, Serres Josep Maria. "Continuous-wave and passively Q-switched solid-state microchip lasers in the near-infrared." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/460758.
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Aquest treball tracta de la caracterització de làsers compactes d'estat sòlid, amb un primer enfocament, l'estudi del
concepte microxip aplicat al làser en diversos hostes cristal·lins dopats amb terres rares. Es reporta els resultats sobre
l'estudi de l'efecte de thermal lens, necessari per a l'obtenció de làser amb aquesta configuració, així com pel
funcionament làser amb continu i polsat utilitzant la tècnica Q-switch.
En els experiments, el concepte microxip es defineix com una cavitat làser quasi monolítica. Aquest concepte s'estudia
per a diferents emissions de làser a ~1.06 m d'ions Yb3+ i Nd3+, a ~1,3 m de Nd3+, a ~1,95 m de Tm3+ hi ha
~2.05 m del Ho3+.
En el règim d'ona contínua s'examina detalladament per als ions de lantànids trivalents esmentats en diversos hostes
cristal·lins amb l'objectiu de comparar el potencial de cada material. En aquest treball, es demostren eficiències molt
properes al límit teòric.
D'altra banda, també es presenten làsers polsats d'estat sòlid amb la configuració microxip amb diversos absorbidors
saturables. Amb aquest propòsit, s'utilitzen com a absorbidors saturables nous nanomaterials com el MoS2, nanoestructures
de carboni (SWCNT, el grafè d'una i de diverses capes) i un SESA. A més, el més convencional Cr:YAG
(~1.06 m) i el Cr:ZnS (~1.9 m) s'examinen per comparar els seus rendiments.Este trabajo trata de la caracterización de láseres compactos de estado sólido, con primer enfoque, el estudio del concepto microchip aplicado al láser en varios huéspedes cristalinos dopados con tierras raras. Se reporta los resultados sobre el estudio del efecto de la thermal lens, necesario para la obtención de láser con esta configuración, así como para el funcionamiento láser en continuo y pulsado utilizando la técnica Q-switch. En los experimentos, el concepto microchip se define como una cavidad láser casi monolítica. Este concepto se estudia para diferentes emisiones de láser a ~1.06 m de los iones Yb3+ y Nd3+, a ~1,3 m de Nd3+, a ~1,95 m de Tm3+ hay ~2.05 m del ion Ho3+. En régimen de onda continua se examina detalladamente para los iones de lantánidos trivalentes mencionados en varios huéspedes cristalinos con el objetivo de comparar el potencial de cada material. En este trabajo, se demuestran eficiencias muy cercanas al límite teórico. Por otra parte, también se presentan láseres pulsados de estado sólido con la configuración microchip con varios absorbedores saturables. Con este propósito, se utilizan como absorbedores saturables nuevos nanomateriales como el MoS2, nano-estructuras de carbono (SWCNT, el grafeno de una y de varias capas) y un SESA. Además, el más convencional Cr:YAG (~1.06 m) y el Cr:ZnS (~1.9 m) se examinan para comparar sus rendimientos
This work deals with the characterization of compact solid state lasers, as a first approach to the study of the microchip laser concept applied to several rare earth-doped crystalline hosts. The results on the study of the thermal lens, required for the microchip laser operation as well as the continuous wave and passive Q-switched laser operation in microchip configuration are reported. In the experiments, the microchip concept is defined as a quasi-monolithic laser cavity. Such a concept is studied for different laser emissions at ~1.06 μm from Yb3+ and Nd3+ ions, at ~1.3 μm from Nd3+, at ~1.95 μm from Tm3+ and at ~2.05 μm from Ho3+. The continuous wave regime is examined in detail for the above mentioned trivalent lanthanide ions embedded in several crystalline hosts with the aim to compare the potential of each gain material. Slope efficiencies very close to the theoretical limit are demonstrated in this work. On the other hand, microchip solid state lasers passively Q-switched with several saturable absorbers are also presented. For this purpose, novel nanomaterials such as MoS2, carbon nanostructures (SWCNTs, single- and multilayer graphene) and a SESA are used as saturable absorbers. Besides, the most conventional Cr:YAG (~1.06 μm) and Cr:ZnS (~1.9 μm) are examined to compare their performance.
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Fabiny, Larry. "Dynamics of a coupled solid state laser array." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/30509.
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Critten, Matthew Peter. "All-solid-state femtosecond Cr:LiSAF and Cr:LiSGaF lasers." Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/13714.
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This thesis describes the development of all-solid-state self-modelocked Cr:LiSAF and Cr:LiSGaF lasers. Diode-pumped colquiriite lasers compare favourably with mainframe-pumped Ti:sapphire lasers, but the conflicting requirements of self-modelocking and pumping by broad-area diodes can cause problems. Two alternatives were investigated. Firstly, high Cr3+ doping permitted pumping in the Cr:LiSAF green absorption trough. Frequency-doubled Nd:YLF and Nd:YAG minilasers offer high-power, diffraction-limited beams in the green. The 'green problem' plagued both minilasers, however, and an Ar-ion pump laser was therefore also used. A laser utilising a 10%-doped AR-coated Cr:LiSAF crystal produced 30 mW output power at 320 mW pump, and 90 fs pulses at 859 nm and 86 MHz repetition rate. The self-modelocking threshold was 280 mW. A laser utilising a 22%-doped Brewster-angled crystal produced 120 mW output power at 1.1 W pump, and 72 fs pulses at 76 mW output. The self-modelocking threshold was 360 mW. 160 mW output was obtained by pumping the crystal at both ends to overcome thermal problems. Secondly, factors affecting CW and self-modelocking thresholds were considered; in particular, the effects of waist size, beam brightness, cavity configuration and intracavity dispersion. A Cr:LiSAF laser, pumped by a self-injection-locked diode, produced sub-100-fs pulses for just 73 mW pump. Its tuning curve was modulated by birefringence effects. The excellent free-running noise properties of the laser permitted a sub-picosecond streak camera evaluation. Two low-threshold lasers utilising low-loss Cr:LiSGaF were also developed. 87 fs pulses at 11.5 mW output power were produced from a Z-cavity laser for 170 mW pump. A laser utilising a compact 'retroreflector' three-minor cavity produced 84- fs pulses at 173 MHz repetition rate for 116 mW pump. Subsequent optimisation led to the production of sub-100-fs pulses for 40 mW pump, with self-modelocked operation demonstrated at pump powers as low as 21 mW.
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Zeller, Simon Christian. "Picosecond solid-state lasers with GHz repetition rates /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16972.
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Parsons-Karavassilis, Duncan. "Diode-pumped all-solid-state lasers and applications." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270946.
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Millas, David Pelaez. "Thin slab and planar waveguide solid state lasers." Thesis, Heriot-Watt University, 1999. http://hdl.handle.net/10399/1174.
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Whitworth, Guy Luke. "Nano-engineered solution processed solid-state semiconductor lasers." Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/12028.
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NOGUEIRA, GUSTAVO B. "Desenvolvimento de lasers no azul, a partir da geracao de segundo harmonico de um laser de Nd:YAG operando em 946nm." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9584.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Ngcobo, Sandile. "Short-pulse generation in a diode-end-pumped solid-state laser." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4225.
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Thesis (MSc (Physics))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: This thesis consists of two parts; the first part is a discussion on the detailed history of the development of different types of modelocked lasers, especially the neodymium-doped lasers. The second part describes the design and development of a modelocked diode-end-pumped solid state Nd:YVO4 laser using Semiconductor Saturable Absorbers. The first part of this work will cover the history of modelocking where different types of lasers were used to generate ultrashort pulses. The discussion will mainly focus on neodymium-doped lasers such as Nd:YVO4, where we will look at the spectral properties such as energy levels, absorption and emission wavelengths of such a laser. The discussion will also look at different types of optical pump sources; such as diode lasers and flashlamps, where we will see the advantages of using diode lasers as pump sources due to their better operating conditions and efficiency. We will also look at two different types of diode pumping setup schemes, which are end-pumping and side pumping; where we will discover that diode-end-pumping is a better scheme for laser mode matching resulting in high efficiency and very good beam quality when compared to side pumping. The gain bandwidth of the laser material will also be discussed showing that a laser material with a very large gain bandwidth and broad emission bandwidth is suitable for generating ultrashort pulses, such as Ti:Sapphire crystal. The discussion will also cover ultrafast lasers that have a small amplification bandwidth suitable for diode-end-pumping and that produce high average output power. Ultrafast lasers with low amplification bandwidth such as Nd:YAG and Nd:YVO4 will be discussed showing that they can generate very short pulses with durations of down to 19 ps and 20 ps respectively and average output powers of 27 W and 20 W. The technique of creating ultrashort pulses which is called modelocking will be discussed, where passive modelocking will be shown to be more suitable for creating ultra short pulses in the femtosecond region and active modelocking in the picosecond region. The discussion will also cover saturable absorbers for passive modelocking where we will discuss the use of semiconductor saturable absorber mirrors to generate reliable self starting modelocked pulses. We will also cover the instabilities associated with using saturable absorbers where we will discuss different methods for reducing the instabilities by using gain media with the smallest saturation fluence. The second part of the work will deal with the design and development of SESAM modelocked diode-end-pumped Nd:YVO4 lasers. This part will include a discussion on the resonator design criteria’s for achieving a stable modelocked diode-end-pumped solid-state laser. The choice of using Nd:YVO4 as a gain medium will be shown to be influenced by its large cross sectional area, which is useful in increasing the gain bandwidth for possible ultrashort pulse generation. The resonator for high power continuous wave (cw) output has been designed using simulation software developed at St Andrews University. We will also discuss stability criteria such as the laser spot size inside the crystal and on the end mirror and how they can be incorporated into the resonator design software. The discussion will also include the pump setup design and the efficient cooling method of the crystal using a copper heat sink. The methodology of obtaining stable, thermal lens invariant, single transverse mode operation during power scaling of Nd:YVO4 lasers will be discussed. A lens relay approach is used to extend the cavity length so as to introduce spot size control in the designed diode-end-pumped Nd:YVO4 laser that will be shown to produce a maximum average output power of 10.5 W with an average beam quality factor M2 of 1.5. We will also discuss the incorporation of a single quantum well SESAM within the extended diode-end-pumped Nd:YVO4 laser resulting in cw-modelocked pulses at an average output power of 2.8 W with pulse repetition frequency of 179 MHz, equivalent to the cavity round trip time of 5.6 ns. The incorporation of the double quantum well SESAM will also be shown to produce stable Q-switched modelocked pulses at an average output power of 2.7 W with pulse repetition frequency of 208 KHz.
AFRIKAANSE OPSOMMING : Hierdie tesis bestaan uit twee dele. Deel 1 is ‘n indiepte bespreking rondom die ontwikkelingsgeskiedenis van Modusgebonde lasers, veral van Neodemiumdoteerde lasers. Deel 2 beskryf die ontwerp en ontwikkeling van ‘n Modusgebonde diodeentgepompde vastetoestand Nd:YVO4 laser deur van ‘n Halfgeleier Versadigbare Absorbeerder (SESAM) gebruik te maak. Die eerste afdeling fokus op Modusbinding om ultrakort pulse te ontwikkel in verskillende tipes lasers. Die bespreking sentreer rondom Neodemiumdoteerde lasers soos Nd:YVO4. In hierdie geval beskou ons ook die spektraaleienskappe van die laser vir beide die absorpsie en emissie golflengtes. Verder word verkillende tipes pompbronne ondersoek (soos diodelasers en flitslampe). Die voordele van diodelasers kom sterk na vore a.g.v. beter werking en effektiwiteit. Verskillende pompopstellings word ook ondersoek naamlik ent-en kantpomping. Entpomping kom hier na vore as die beter opsie i.t.v. laser-moduspassing. Dit lei tot ‘n hoër effektiwiteit wat ‘n beter straalkwaliteit tot gevolg het, in vergelyking met kantgepompde opstellings. Die versterkingsbandwydte word ook bespreek: ‘n groot versterkingsbandwydte en breë emissiebandwydte is geskik om ultrakort pulse te ontwikkel. Ti:Saffier is ‘n goeie voorbeeld. Ultravinnige lasers met ‘n klein versterkingsbandwydte word ook bespreek aangesien dit geskik is vir diodeentpomping wat dan ‘n hoë gemiddelde uitsetdrywing lewer. Nd:YAG en Nd:YVO4 word ondersoek en daar word getoon dat hul pulse van so kort as 19 ps en 20 ps onderskeidelik teen ‘n gemiddelde uitsetdrywing van 27 W en 20 W kan lewer. Die tegniek waarmee ultrakort pulse geskep word is Modusbinding: passiewe modusbinding is meer geskik vir femtosekonde pulse en aktiewe modusbinding is meer geskik vir pikosekonde pulse. Verder word versadigbare absorbeerders bespreek, vir hul gebruik in die betroubare selfinisiërende modusgebonde pulse. Die onstabiliteite geassosieer met versadigbare absorbeerders word ook bespreek asook verskillende metodes om dit te minimaliseer. Die tweede afdeling behandel die ontwerp en ontwikkeling van ‘n SESAM modusgebonde diode-entgepompde Nd:YVO4 laser. Die resonator ontwerpspesifikasies vir stabiele werking word ook bespreek. Die keuse van Nd:YVO4 as versterkingsmedium is a.g.v. die groot deursnitarea wat die versterkingsbandwydte verhoog, om ultrakort pulse te genereer. Die resonator vir hoë drywing kontinuestraal werking is ontwerp deur van St Andrews sagteware gebruik te maak. ‘n Bespreking van stabiliteitsspesifikasies soos die laser kolgrootte, binne die kristal asook op die entspieël volg, asook die pompmetodiek en effektiewe verkoeling van die kristal. Die totale metodiek rondom die verkryging van ‘n stabiele, termieselens invariante, enkele transversale modus laser word bespreek met die oog op drywingsverhoging. Die geval onder bespreking is waar die laser se kolgrootte beheer kan word op die entspieël deur die resonatorlengte aan te pas. Dit word getoon dat dit ‘n kontinuestraal laser van 10.5 W drywing kan lewer teen die maksimum gemiddelde straalkwaliteit van M2 = 1.5. Die byvoeging van ‘n enkele kwantumput SESAM in die laser het modusgebonde pulse tot gevolg. Die gemete waardes was 2.8 W gemiddelde drywing met ‘n pulsherhalingstempo van 179 MHz wat in lyn is met die pulsbewegingstyd in die resonator van 5.6 ns. Deur van ‘n dubbele kwantumput SESAM gebruik te maak word Q-geskakelde modusgebonde pulse verkry, teen ‘n gemiddelde uitsetdrywing van 2.7 W en ‘n pulsherhalingstempo van 208 KHz.
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KORES, CRISTINE C. "Desenvolvimento de um laser Raman com bombeamento transversal em configuração de ângulo rasante." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23824.
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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Stumpf, Max Christoph. "Diode-pumped solid-state lasers for frequency comb generation." Konstanz Hartung-Gorre, 2010. http://d-nb.info/1000806235/04.
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Smith, Gerald Robert. "Solid-state adaptive lasers and amplified spontaneous emission sources." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497619.
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Lubeigt, Walter. "Intra-cavity adaptive optics control of solid-state lasers." Thesis, University of Strathclyde, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431784.
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Bierstedt, Andreas. "Implementing Diode-Pumped Solid-State Lasers into Instrumental Analytics." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19525.
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Eine der bedeutendsten technischen Errungenschaften des letzten Jahrhunderts beinhaltet
zweifelsfrei die Erfindung des Lasers. Bereits wenige Jahrzehnte nach seiner ersten technischen Umsetzung ist er heute aus so unterschiedlichen Anwendungsbereichen wie der
Mess- und Regeltechnik, der Unterhaltungselektronik, sowie der industriellen Fertigung
und Materialbearbeitung nicht mehr wegzudenken. Die analytische Chemie bildet hier
keine Ausnahme. Die Möglichkeit mittels Laserstrahlung sowohl räumlich als auch zeitlich
definiert einen maßgeschneiderten Energieeintrag in Materialsysteme vorzunehmen, wird
heute umfangreich in diversen Analyseverfahren eingesetzt. Ein Meilenstein auf dem Gebiet
der Laserentwicklung stellt die Einführung diodengepumpter Festkörperlaser (DPSS)
dar. Diese neuartige Lasergeneration vereint die Vorteile einer begünstigten Energiebilanz
durch resonante Anregung im Lasermedium mit einer erhöhten Flexibilität der zeitlichen
Modulation der Laserausgangsleistung. Während DPSS Laser auf dem Gebiet der Materialbearbeitung bereits die Hälfte des Marktanteils ausmachen, finden sie bislang in den
analytischen Wissenschaften nur wenig Verbreitung. Auch hier könnten die inhärenten
Vorteile von DPSS Lasern bezüglich Konversionseffizienz, Stabilität, Flexibilität und Strahlprofil maßgeblich zu einer Optimierung relevanter Teilschritte beitragen. Die vorliegende Arbeit schließt diese Lücke, indem sie die Anwendbarkeit eines modernen DPSS Lasers für solch unterschiedliche Aufgaben wie der Laserablation, der Raman-Spektroskopie, der atomaren und molekularen Emissionsspektroskopie, bis hin zur Erzeugung eines neuartigen quasi-kontinuierlichen, luftgetragenen Plasmas für die Atmosphärendruck-Ionisation untersucht. In allen Studien konnten die Verbesserungen der jeweiligen analytischen Verfahren auf die Eigenschaften des verwendeten Lasers zurückgeführt werden.Without any doubt, one of the most momentous technical achievements of the last century has been the invention of the laser. Today, merely some decades after its first technical realization, the laser has established a leading role in such broad application fields as sensing and control engineering, consumer electronics, as well as industrial production and materials processing. Analytical chemistry does not make an exception. The possibility of both spatially and temporally well-confined introduction of precisely dosed and defined energy into any material is nowadays widely exploited in a plethora of analytical techniques. A milestone in the field of laser technology was the advent of diode-pumped solid-state (DPSS) lasers. This new generation of laser systems combines the benefits of an advantageous energy balance, caused by resonant excitation of the laser medium, with an enhancement in flexibility in terms of modulation of the laser output. While DPSS lasers already account for half of the devices used in materials processing, the dissemination in the analytical sciences has so far hardly occurred. Also here, the inherent advantages of DPSS lasers regarding efficiency, reliability, flexibility, and beam profile could greatly contribute in a multitude of analytically relevant sub-steps. This thesis closes this gap by studying the applicability of a current state-of-the-art DPSS laser for as different tasks as laser ablation, Raman spectroscopy, atomic and molecular emission spectroscopy, all the way to generating a generally new quasi-continuous airborne plasma for ambient ionization. In all cases studied, the improvement of the respective analytical techniques could be ascribed to the intrinsic properties of the used laser.
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Smith, Callum Robertson. "Power scaling architectures for solid-state and fiber lasers." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/419482/.
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This thesis focuses on developing power scaling architectures for solid-state and fiber lasers. The thermally-guided fiber-rod (TGFR) laser is suggested as a novel power scalable concept. This device lies in a domain between bulk rod lasers and traditional fiber lasers. The motivation is to benefit from the excellent thermal management properties of fibers, whilst negating deleterious nonlinear effects owing to the tight beam confinement and long interaction lengths that plague high power fiber lasers. An elegant thermal guiding technique is proposed to provide mode control with the TGFR. We derive the refractive index profile that ensues as a result of end-pumping the TGFR with a fiber-coupled diode laser. Furthermore, we construct a model that predicts the resulting impact on Gaussian beam propagation through the TGFR for various pump configurations. A model describing the gain within the device is derived from the laser rate equations. These two models allow us to predict amplifier and laser performance of the TGFR device. We initially suggest soft glass as a host material for the TGFR, owing to the ability to dope this material with rare-earth ions in significantly higher concentrations than silica which is the traditional material of choice for fiber lasers, thus allowing the realisation of shorter devices. The requirements of a soft glass host are discussed in terms of both device fabrication and laser operation. Three potential sources are identified, including an in-house manufactured neodymium-doped and undoped phosphate glass, a commercial neodymium-doped and undoped silicate glass, and a neodymium-doped and undoped phosphate glass obtained through collaboration. The fabrication of potential TGFR devices with these three sources is described. This is followed by a laser investigation of these devices, where the issues of glass homogeneity and transmission loss become apparent, which are largely attributed to poor glass quality and unsuitable compatibility between the doped and undoped glasses. The neodymium-doped phosphate obtained through collaboration performed best, with a maximum output power around 1054nm of 2.5W, with a slope efficiency with respect to launched pump power of 28.5%. However, the poor glass quality prevented the thermal guiding investigation, and thus the beam quality was dictated by the highly multimode guide, resulting in a beam propagation factor of M2 = 60. Additionally, although this device had the lowest loss of the three sources, a significant loss of 5.7dB/m was measured using the Findlay-Clay analysis. In light of these glass quality issues, the TGFR concept was fully tested using an extra-large mode area silica fiber. A mode guiding investigation revealed that an in-built non-uniform refractive index profile was responsible for providing a degree of guiding, even in the absence of pumping. This guiding was well predicted by assuming a parabolic refractive index profile and utilising the mode guiding model. Furthermore, the thermal guiding model gave excellent agreement with measured data across a range of launched pump powers up to 30W. The device was operated as an amplifier for seed beams at 976nm and 1030nm, and good agreement with the gain model was observed. At 976nm a maximum gain of 4.1dB was achieved for a 60mW seed resulting in an output power of 155mW, and 2.2dB for a 450mW seed resulting in an output power of 750mW. For 1030nm a maximum gain of 5.0dB was achieved for a 50mW seed resulting in an output power of 160mW, and 3.9dB for a 1.1W seed resulting in an output power of 2.7W. Excellent beam quality was maintained throughout amplification with M2 < 1.1 at the maximum gain levels for both 976nm and 1030nm. The concept was extended to a laser configuration at for both the 975nm and 1030nm transition. A device operating at 1032.5nm achieving a maximum output power of 13.1W with a slope efficiency of 44% with respect to launched power and 53% with respect to absorbed power. Excellent beam quality was achieved at maximum output power with M2 < 1.1. Additionally, a device operating at 978.5nm achieved a maximum output power of 1W with a slope efficiency of 8% with respect to launched power. Again, excellent beam quality was achieved at maximum output power with M2 < 1.1. The slope efficiencies of both of these devices, particularly the latter, are expected to increase with higher pump powers. An Yb:YAG thin-slab architecture is suggested as a power scalable architecture for cylindrical vector (CV) beams, which have promising applications within materials processing. A seed source is constructed for operation at 1030nm, which exploits thermally-induced bi-focusing to produce a radially polarised output beam with a maximum output power of 6.9W, with a conversion efficiency of 41% with respect to absorbed pump power. The beam quality was measured as M2 = 2.3, whilst the radial polarisation extinction ratio (RPER) was > 15dB. It was demonstrated that the seed source could be amplified in a highly asymmetric thin-slab gain medium whilst maintaining radial polarisation purity. The implications of the Gouy phase shift owing to astigmatic focusing within the slab are discussed. Amplifier experiments yielded a gain of 7.5dB for a 25mW seed input power, and 4.4dB for a 1.45W seed input power, resulting in a maximum output power of 4W.The beam propagation factor at the maximum gain level was maintained at the lowest seed input power at M2 = 2.3, and was only slightly degraded to M2 = 2.4 at the highest seed input powers. Crucially, the RPER was maintained at >15dB for both cases.
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Hayward, Robert Alan. "High-power diode-pumped solid-state 2 micron lasers." Thesis, University of Southampton, 2003. https://eprints.soton.ac.uk/41525/.
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Brightness scaling of diode-bar end-pumped solid-state lasers producing efficient output radiation in the 2 μm wavelength region is investigated. Problems and strategies for power scaling diode-bar end-pumped lasers in the 2μm region are also discussed. Thermal lens measure ments on Tm3+:YAG and Tm3+:(Lu,Y)AG were made. Thermal lens dependency on resonator loss is observed and attributed to heating from upconversion. High-power room temperature diode-bar end-pumped Tm3+:(Lu,Y)AG were developed. Efficient high power operation of the Tm3+:YAG laser producing 14.2W of output power at 2.013μm for 53.4W of incident pump power is demonstrated with M(2) values of 1.3 in orthogonal planes. The laser was then linearly polarised and compared with a similar laser using a scheme to compensate for the loss caused by thermally induced de-polarisation. Before the de-polarisation loss prevented lasing operation an output power of 8.4W was observed. Using the compensation scheme, the laser produced 11.5W of output power and was limited by pump power. The uncompensated de-polarisation loss was >5% reducing to <0.4% for the compensated laser. A high power Tm3+:(Lu,Y)AG laser producing 18W of output power at 2.022μm was demonstrated and compared with a Tm3+:YAG laser. High-power intracavity pumped Ho3+:YAG lasers were developed. A collinearly intracavity pumped Ho3+:YAG laser producing 8.4W of output power is demonstrated though application of the brightness scaling strategy was difficult to implement. A non-collinearly intracavity pumped laser showing 1.6W of output power is reported but showed alignment instability and was hard to replicate. Intracavity pumping schemes are discussed. A Tm3+:silica fibre laser produced 14.2W of output at 1.98μm for 38.3W of launched pump power with a slope efficiency of ~36%. This was the highest reported power from a Tm3+:silica fibre laser to the author's knowledge. A tunable Tm3+ fibre laser showed > 1.8W output power across a tuned wavelength range of 1870-2030 nm.
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Hardman, Paul Joseph. "Power-scaling of diode-end-pumped solid-state lasers." Thesis, University of Southampton, 1999. https://eprints.soton.ac.uk/351506/.
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This thesis presents a strategy for power-scaling diode-end-pumped solid-state lasers to multiwatt output power whilst retaining the high-efficiency and diffraction-limited beam quality, that have been characteristic of operation at low powers. This strategy reduces the detrimental effect of energy transfer upconversion (ETU), which can decrease the lifetime of the upper-laser-level and also increase the heat generated inside the laser material. An analytical description of the lifetime quenching and increased thermal lensing due to ETU is presented. Using this analytical model it is shown that ETU can be reduced by decreasing the absorption coefficient, by increasing the spot size or by decreasing the upconversion parameter, W. This strategy is applied to a Nd:YLF laser. Before designing the laser the published value of the upconversion parameter for Nd:YLF is confirmed as W = (1.7 ± 1) x 10−16cm3s−1, by observing the fluorescence saturation with increasing pump power. Also, without applying the power-scaling strategy, the thermal lensing in Nd:YLF in a typical pump set-up is determined, under lasing and non-lasing conditions. A significant difference between the thermal lensing under non-lasing and lasing conditions is observed which is attributed to the increase in heat input caused by ETU. In a standing-wave cavity, under cw lasing conditions and at the maximum pump power (29.5 W incident, 27.4 W absorbed) an output power of 11.1 W is obtained. This laser has excellent beam quality (M2x,y, < 1.1) throughout the pump power range. An intracavity-frequency doubled ring laser is also demonstrated. This laser produces >10W of single-frequency output with a 10% output coupler (~9.7 W at 1.053μm and ~0.6 W at 526.5 nm) at the maximum pump power. With a high reflector, for 1.053 μm, 6.2 W of polarised output (8.3 W generated inside the LBO), at 526.5mn is obtained. The output has excellent beam quality (M2x,y < 1.2) and amplitude stability (<± 0.5%). The mode-hopping suppression obtained in this laser is also investigated. A large tuning range (~42 GHz, ~80 axial mode-spacings) with the laser optimised for 1053mn output (i.e. with the 10% output coupler) is achieved with both diode-bars at full pump power. Also a large tuning range is achieved with the laser optimised for green output with one diode-bar (~72 GHz, ~150 axial mode-spacings). The upconversion problems are also sufficiently reduced to successfully demonstrate a highly efficient Q-switched ring laser. This laser overcomes the slow switching speed of the A-O modulator by taking the output through the diffracted beam. ~3.5mJ of single-frequency TEM00 energy for ~25W of incident pump power is demonstrated. This laser is then used to pump an OPO and preliminary results are presented.
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Ghiti, Ali. "Valence band engineering in semiconductor lasers." Thesis, University of Surrey, 1990. http://epubs.surrey.ac.uk/842853/.
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This thesis is concerned with the improvement of semiconductor laser characteristics using valence band engineering. We first show that the combination of strain and quantum confinement can confer considerable advantages to long wavelength lasers. With sufficient built-in strain, the highest hole subband has a low effective mass and is well separated from the lower bands. The low effective mass reduces the carrier density needed for population inversion and leads to the virtual elimination of two important loss mechanisms: Auger recombination and intervalence band absorption. We propose a specific strained-layer 1.55mum structure that can reduce the threshold current density and its temperature dependence and increase the luminescent efficiency. The presence of strain can also lead to an enhancement of the relaxation oscillation frequency due to the higher differential gain when compared to lattice-matched structures. The linewidth enhancement factor is also predicted to be reduced. Such strained-layer lasers could be of major significance for long distance optical communication. However, the long term stability of these structures, although promising, has still to be fully assessed. In view of this, we suggest that (111) growth of unstrained structures could provide the light-hole cap to the valence band needed for laser operation. We find that the threshold current density in thin (111) lasers could be reduced while the polarisation selection of TE modes could be improved compared to equivalent (001) lasers. Finally, we consider the effects of crystal orientation and of strain on the exciton binding energy.
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Kalfoutzos, Aristeidis. "Free electron and solid state lasers development for naval directed energy." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Dec%5FKalfoutzos.pdf.
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Thesis (M.S. in Applied Physics and M.S. in Electrical Engineering)--Naval Postgraduate School, December 2002.Thesis advisor(s): William B. Colson, Phillip E. Pace. Includes bibliographical references (p. 101-102). Also available online.
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Jenkins, Stephen Derek. "Modification of polymer surfaces using excimer lasers." Thesis, University of Hull, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291960.
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Sylvan, Alan. "A study of small solid-state switched tea CO2 lasers." Thesis, Heriot-Watt University, 1991. http://hdl.handle.net/10399/831.
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Chesworth, Andrew Alexander. "Mode control in thin slab, diode pumped solid state lasers." Thesis, Heriot-Watt University, 1998. http://hdl.handle.net/10399/649.
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Major, Arkady. "Diode-pumped passively mode-locked ultrashort pulse solid-state lasers." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273384.
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Kallmeyer, Frank. "Wavelength controlled solid state lasers with high output pulse energy." Berlin mbv, 2009. http://d-nb.info/993935974/04.
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Lu, Min. "Performance of continuously pumped, passively Q-switched, solid state lasers." Thesis, University of Sussex, 2011. http://sro.sussex.ac.uk/id/eprint/6953/.
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This thesis studies the relationship between the pairs of resonator output coupling and intra-cavity absorber initial transmission, and the FWHM (full width at half maximum) pulse duration of a continuously pumped passively Q-switched solidstate laser, when the output energy is pre-determined. Depending on the magnitude of the pumping power, three different rate equation models are used to evaluate the required output coupler reflectivity and absorber initial-transmission pair for the corresponding FWHM pulse duration. The energy transfer kinetics of the passively Q-switched laser decides the required pumping power; and the pair of output coupler reflectivity absorber transmission pair, determine the build-up time of Q-switching and the repetition rate of the laser system. Hence, the forms of the models are controlled by two conditions: 1) the build-up time of Q-switching; and 2) the recovery time of the absorber. When the build-up time of Q-switching is relatively short, but the recovery time of the absorber is long, Model I is based on the simplified laser rate equations. It is used to evaluate the output coupler reflectivity and absorber initialtransmission pair, which satisfies the pre-determined output energy and FWHM pulse duration. Model II is set up to study the case when both the build-up time of Q-switching and the recovery time of the absorber are long. In Model II, the laser rate equations are solved using the Runge-Kutta method. Model III simulates the case when the recovery time of the absorber is short. To validate the models, the simulation results of practical passively Q-switched laser systems are compared with experimental results reported in the literature. The agreement of the simulation results with reported experimental results demonstrates the importance of the boundary conditions for the different cases, and verifies the soundness of the models. Generalizing the simulation results, obtained from different passively Q-switched laser systems with different pumping power and different pre-determined output energy, yields general conclusions which permit a designer to select the correct parameters for a desired laser performance.
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Lin, Di. "Doughnut-shaped beam generation in solid-state and fibre lasers." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/399926/.
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This thesis focuses on developing new techniques for generating doughnut-shaped beams with a radial polarization state or a vortex phase front. An all-fibre-based pump beam conditioning element based on a tapered capillary fibre has been developed to provide a ring-shaped pump beam for end-pumped solid-state lasers. This unique pumping scheme provides a simple, efficient and robust approach for generating the doughnut-shaped first higher-order Laguerre-Gaussian (LG01) mode due to its optimized spatial overlap for the LG01 mode. However, the analysis of mode composition shows the doughnut-shaped LG01 mode is apt to be a ‘hybrid’ mode consisting of TEM01 modes with orthogonal orientations and LG01 modes with opposite handedness of helical phase front at axial modes with different frequencies. A novel mode selection element consisting of two nanoscale thickness aluminium strips has been developed by exploiting the fact that the standing wave intensity distribution for the LG01+ and LG01- modes inside a laser resonator are different. This scheme has been demonstrated for the first time in a diode-pumped Nd:YAG laser to generate an LG01 mode with controllable handedness of helical phase front at output powers ~1 W. Using the ring-shaped pumping scheme, direct generation of a radially-polarized beam has been successfully demonstrated in a Nd:YAG laser by exploiting the fact that the radially-polarized and azimuthally-polarized beams have slightly different spatial overlaps with the ring-shaped pump beam due to bifocusing within the laser crystal, thus resulting in a different threshold for each mode. The ring-shaped pumping scheme also provides flexibility in transverse mode selection and a significant reduction in adverse thermal lensing effects, offering the prospect of power scalability in end-pumped lasers. 14 W of linearly-polarized TEM00 mode output with a beam quality factor (M2) < 1.1 and 16 W of linearly-polarized doughnut-shaped LG01 mode with M2<2.2 were obtained in a Nd:YVO4 laser with a slope efficiency of 53% and 55%, respectively. The results showed a reduction in thermal lens strength by approximately 30% compared with traditional fibre-coupled laser diode end pumping. Furthermore, I have investigated extracavity conversion to radial polarization in both 1µm and 2µm regimes using continuously space-variant lambda/4 or lambda/2 waveplates (also called S-waveplates), fabricated by a recently developed femtosecond writing technique. In the one-micron wavelength regime, the lambda/2 S-waveplate can transform a linearly polarized Gaussian beam into a radially polarized beam with a conversion efficiency of ~75% and M2 of 2.7, whilst the lambda/4 S-waveplate can transform a circularly polarized LG01 mode into radial polarization with a conversion efficiency of ~86% and M2 of 2.9. The S-waveplate has a much better performance in longer wavelength regime due to reduced Rayleigh scattering. We demonstrate highly efficient conversion (~86%) to radial polarization in the 2µm band with wavelength tuning from 1950nm to 2100nm by using a 2µm lambda/2 S-waveplate. The resulting radially polarized beam had a M2 of 2.1 and a maximum polarization extinction ratio (PER) of 17.5dB at 2050nm with a variation of less than 3dB over the full wavelength range. I finally exploited the lambda/2 S-waveplate as an intracavity polarization-controlling element to directly excite radially-polarized TM01 mode operation in an Yb-doped fibre laser. The laser yielded ~32W of output power with a radially-polarized TM01 mode output beam at 1040nm with a slope efficiency of 66% and polarization purity of 95%. Moreover, I have demonstrated a simple technique for selectively generating the fundamental LP01 mode and the next higher order doughnut-shaped LP11 mode with a vortex phase front in an Yb-doped fibre laser. This approach exploits the difference in polarization behaviour of individual transverse modes due to transverse variation of birefringence in a few-moded fibre, allowing robust mode discrimination through the use of an appropriately aligned intracavity polarizing element. The laser yielded ~36W of output power for both transverse modes with slope efficiency of 74% and a mode purity of 95%.
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Poutous, Menalaos. "Stable continuous-wave operation of Ti:Sapphire lasers in higher-order transverse Hermite-Gaussian modes." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/29877.
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Mansfield, Robb P. "High energy solid state and free electron laser systems in tactical aviation." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Jun%5FMansfield.pdf.
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