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1
Gonzalez, Francisco Javier. "Antenna-coupled infrared focal plane array." Doctoral diss., University of Central Florida, 2003. http://digital.library.ucf.edu/cdm/ref/collection/RTD/id/22899.
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University of Central Florida College of Engineering ThesisIn this dissertation a new type of infared focal plan array (IR FPA) was investigated, consisting of antenna-coupled microbolometer fabricated using electron-beam lithography. Four different antenna designs were experimentally demonstrated at 10-micron wavelength: dipole, bowtie, square-spiral, and log-periodic. The main differences between these antenna types were their bandwidth, collection area, angular reception pattern, and polarization. To provide pixel collection areas commensurate with typical IR FPA requirements, two configuration were investigated: a two-dimensional serpentine interconnection of invididual IR antennas, and a Fresnel-zone-plate (FZP) coupled to a single-element antenna. Optimum spacing conditions for the two-dimensional interconnect were developed. Increased sensitivity was demonstrated using a FZP-coupled design. In general, it was found taht the configuration of the antenna substrate material was critical for optimization of sensitivity. The best results were obtained using this membranes of silicon nitride to enhance the thermal isolation of the antenna-coupled bolometers. In addition, choice of the bolometer material was also important, with the best results obtained using vanadium oxide. Using optimum choices for all parameters, normalized sensitivity (D*) values in the range of mid 108 [cm√Hz/W] were demonstrated for antenna-coupled IR sensors, and directions for further improvements were identified. Successful integration of antenna-coupled pixels with commercial readout integrated circuits was also demonstrated.
Ph.D.;
Electrical Engineering and Computer Science;
Engineering and Computer Science;
170 p.
xii, 170 leaves, bound : ill. ; 28 cm.
2
Newman, Kevin, and Kevin Newman. "Achromatic Phase Shifting Focal Plane Masks." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621110.
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The search for life on other worlds is an exciting scientific endeavor that could change the way we perceive our place in the universe. Thousands of extrasolar planets have been discovered using indirect detection techniques. One of the most promising methods for discovering new exoplanets and searching for life is direct imaging with a coronagraph. Exoplanet coronagraphy of Earth-like planets is a challenging task, but we have developed many of the tools necessary to make it feasible. The Phase-Induced Amplitude Apodization (PIAA) Coronagraph is one of the highest-performing architectures for direct exoplanet imaging. With a complex phase-shifting focal plane mask, the PIAA Complex Mask Coronagraph (PIAACMC) can approach the theoretical performance limit for any direct detection technique. The architecture design is flexible enough to be applied to any arbitrary aperture shape, including segmented and obscured apertures. This is an important feature for compatibility with next-generation ground and space-based telescopes. PIAA and PIAACMC focal plane masks have been demonstrated in monochromatic light. An important next step for high-performance coronagraphy is the development of broadband phase-shifting focal plane masks. In this dissertation, we present an algorithm for designing the PIAA and PIAACMC focal plane masks to operate in broadband. We also demonstrate manufacturing of the focal plane masks, and show laboratory results. We use simulations to show the potential performance of the coronagraph system, and the use of wavefront control to correct for mask manufacturing errors. Given the laboratory results and simulations, we show new areas of exoplanet science that can potentially be explored using coronagraph technology. The main conclusion of this dissertation is that we now have the tools required to design and manufacture PIAA and PIAACMC achromatic focal plane masks. These tools can be applied to current and future telescope systems to enable new discoveries in exoplanet science.
3
Escorcia, Carranza Ivonne. "Metamaterial based CMOS terahertz focal plane array." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6955/.
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The distinctive properties of terahertz radiation have driven an increase in interest to develop applications in the imaging field. The non-ionising radiation properties and transparency to common non-conductive materials have led research into developing a number of important applications including security screening, medical imaging, explosive detection and wireless communications. The proliferation of these applications into everyday life has been hindered by the lack of inexpensive, compact and room-temperature terahertz sources and detectors. These issues are addressed in this work by developing an innovative, uncooled, compact, scalable and low-cost terahertz detector able to target single frequency imaging applications such as stand-off imaging and non-invasive package inspection. The development of two types of metamaterial (MM) based terahertz focal plane arrays (FPAs) monolithically integrated in a standard complementary metal-oxide semiconductor (CMOS) technology are presented in this Thesis. The room temperature FPAs are composed of periodic cross-shaped resonant MM absorbers, microbolometer sensors in every pixel and front-end readout electronics fabricated in a 180 nm six metal layer CMOS process from Texas Instruments (TI). The MM absorbers are used due to the lack of natural selective absorbing materials of terahertz radiation. These subwavelength structures are made directly in the metallic and insulating layers available in the CMOS foundry process. When the MM structures are distributed in a periodic fashion, they behave as a frequency-selective material and are able to absorb at the required frequency. The electromagnetic (EM) properties are determined by the MM absorber geometry rather than their composition, thus being completely customisable for different frequencies. Single band and broadband absorbers were designed and implemented in the FPAs to absorb at 2.5 THz where a natural atmospheric transmission window is found, thus reducing the signal loss in the imaging system. The new approach of terahertz imaging presented in this Thesis is based in coupling a MM absorber with a suitable microbolometer sensor. The MM structure absorbs the terahertz wave while the microbolometer sensor detects the localised temperature change, depending on the magnitude of the radiation. Two widely used microbolometer sensors are investigated to compare the sensitivity of the detectors. The two materials are Vanadium Oxide (VOx) and p-n silicon diodes both of which are widely used in infrared (IR) imaging systems. The VOx microbolometers are patterned above the MM absorber and the p-n diode microbolometers are already present in the CMOS process. The design and fabrication of four prototypes of FPAs with VOx microbolometers demonstrate the scalability properties to create high resolution arrays. The first prototype consists of a 5 x 5 array with a pixel size of 30 μm x 30 μm. An 8 x 8 array, a 64 x 64 array with serial readout and a 64 x 64 array with parallel readout are also presented. Additionally, a 64 x 64 array with parallel output readout electronics with p-n diode microbolometers was fabricated. The design, simulation, characterisation and fabrication of single circuit blocks and a complete 64 x 64 readout integrated circuit is thoroughly discussed in this Thesis. The absorption characteristics of the MMs absorbers, single VOx and p-n diode pixels, 5 x 5 VOx FPA and a 64 x 64 array for both microbolometer types demonstrate the concept of CMOS integration of a monolithic MM based terahertz FPA. The imaging performance using both transmission and reflection mode is demonstrated by scanning a metallic object hidden in a manila envelope and using a single pixel of the array as a terahertz detector. This new approach to make a terahertz imager has the advantages of creating a high sensitivity room temperature technology that is capable of scaling and low-cost manufacture.
4
Thvedt, Tom Arnold 1956. "Computer model of a focal plane array." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276703.
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The background and operation of charge transfer devices is reviewed, and a computer model simulation of focal plane arrays is presented. The model provides an option to predict the performance of a focal plane. With this program, any of the allowed materials, detectors, readout structures, or preamplifiers that make up a focal plane, may be selected to create new designs for analysis. Only surface channel devices are considered, and only references to the spectral dependence are presented. The computer model's operation and validity is supported by over 70 equations and more than 50 figures, including actual computer screen printouts. Standard equations followed by brief discussions are used to support the menu driven program. The structure and operation of the computer model is presented, but not the actual software source code.
5
Martin, Paul Scott. "Quantum well intersubband photodetectors in focal plane arrays." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41788.
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6
Umminger, Christopher Bruce. "Integrated analog focal plane processing for automatic alignment." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36019.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 161-168).
by Christopher Bruce Umminger.
Ph.D.
7
Zhou, Sichao. "Structured Light from Pupil Plane to Focal Field." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1596569999236042.
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8
Brooks, Keira J., Laure Catala, Matthew A. Kenworthy, Steven M. Crawford, and Johanan L. Codona. "Polarization dOTF: on-sky focal plane wavefront sensing." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622419.
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The differential Optical Transfer Function (dOTF) is a focal plane wavefront sensing method that uses a diversity in the pupil plane to generate two different focal plane images. The difference of their Fourier transforms recovers the complex amplitude of the pupil down to the spatial scale of the diversity. We produce two simultaneous PSF images with diversity using a polarizing filter at the edge of the telescope pupil, and a polarization camera to simultaneously record the two images. Here we present the first on-sky demonstration of polarization dOTF at the 1.0m South African Astronomical Observatory telescope in Sutherland, and our attempt to validate it with simultaneous Shack-Hartmann wavefront sensor images.
9
Bolat, Beldek Tugba. "Short Wave Infrared Camera Design And Focal Plane Analysis." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614150/index.pdf.
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The subject of this study is the design of a camera, which has maximum volume of 50 mm x 50 mm x 300 mm, using short infrared wavelength providing Rayleigh criteria. Firstly, the required flux per pixel has been calculated. Throughout these calculations, atmospheric losses have been obtained by MODTRAN program. Also signal to noise ratio has been examined at minimum and maximum integration time intervals. The focal length of the camera has been calculated as it receives 1 m resolution from 8 km distance. Moreover, the lens materials have been used as N-F2, LIF and BaF2 in this six lens system. The design has been done using ZEMAX optical design program and the performance of the system at focal plane was investigated by the help of Seidel aberrations, Modulation transfer Function (MTF), Spot diagram and Optical Path Difference (OPD) fan plot analyses.
10
Joo, Youngjoong. "High speed image acquisition system for focal-plane-arrays." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/14455.
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11
Lange, Davis Alan 1964. "MBE-deposited iridium silicides for focal plane array applications." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282386.
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Iridium silicides are of current interest as candidate detector materials for silicon based, Schottky-barrier infrared focal plane arrays. In this work, the growth and structure of codeposited IrSi₃ and Ir₃Si₄ films is discussed as well as the effect of annealing and deposition temperature on pure Ir film depositions. Nearly single-phase polycrystalline IrSi₃ films were formed by codeposition of Ir and Si in a 1:3 ratio at temperatures as low as 450°C. Localized epitaxial crystallite growth, identified by x-ray and electron diffraction, is found for IrSi₃ films formed at temperatures >600 °C, with a previously unreported c-axis epitaxial crystallite growth on Si(111) dominating at ∼700 °C. Single-phase polycrystalline Ir₃Si₄ films were formed by annealing room temperature 3:4 codeposited films, whereas localized epitaxial Ir₃Si₄ crystallite growth occurred for codeposition at temperatures of ∼500 °C. Annealed Ir films initially form IrSi crystallites at temperatures of ∼350 °C and further react with the substrate to form polycrystalline Ir₃Si5 at temperatures ≥ 550 °C. The Ir₃Si₄ phase, not found in annealed reactions, dominated the growth of silicide films formed by hot Ir depositions at 500 °C. A previously unreported Ir₃Si₄ epitaxial growth was identified for Ir depositions on Si(111)substrates. Resistivity measurements indicate that IrSi₃, IrSi, and Ir₃Si₄ films are metallic, where Ir₃Si₄ had the lowest resistivity of ∼60 μΩ-cm. Optical photoresponse and I-V measurements performed on diode structures indicate the barrier height of IrSi₃ on p-type Si(111) (∼0.33 eV) to be higher than that on p-type Si(100) (∼0.22-0.25 eV), limiting infrared imaging capability to the SWIR (1-3 μm) and MWIR (3-5 μm) atmospheric transmission windows, respectfully. Codeposited Ir₃Si₄ films display optical barrier heights between 0.125 to 0.175 eV on p-type Si(100), providing possible imaging capability in the LWIR (8-12 μm) spectral region. Ir₃Si₄ devices, displaying localized epitaxial crystallite growth, yield higher emission efficiency than polycrystalline Ir₃Si₄ films. Optical photoresponse measurements on a IrSi device also indicate a low optical barrier height (∼0.12 eV) providing access to the LWIR spectral region. Optical measurements on Ir₃Si5 films are also presented.
12
Ball, Jesse Grant. "NCPA Optimizations at Gemini North Using Focal Plane Sharpening." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/613384.
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Non-common path aberrations (NCPA) in an adaptive optics system are static aberrations that appear due to the difference in optical path between light arriving at the wavefront sensor (WFS) and at the science detector. If the adaptive optics are calibrated to output an unaberrated wavefront, then any optics outside the path of the light arriving at the WFS inherently introduce aberrations to this corrected wavefront. NCPA corrections calibrate the adaptive optics system such that it outputs a wavefront that is inverse in phase to the aberrations introduced by these non-common path optics, and therefore arrives unaberrated at the science detector, rather than at the output of the corrective elements. Focal plane sharpening (FPS) is one technique used to calibrate for NCPA in adaptive optics systems. Small changes in shape to the deformable element(s) are implemented and images are taken and analyzed for image quality (IQ) on the science detector. This process is iterated until the image quality is maximized and hence the NCPA are corrected. The work carried out as described in this paper employs two FPS techniques at Gemini North to attempt to mitigate up to 33% of the adaptive optics performance and image quality degradations currently under investigation. Changes in the NCPA correction are made by varying the Zernike polynomial coefficients in the closed-loop correction file for Altair (the facility adaptive optics system). As these coefficients are varied during closed-loop operation, a calibration point-source at the focal plane of the telescope is imaged through Altair and NIRI (the facility near-infrared imager) at f/32 in K-prime (2.12 μm). These images are analyzed to determine the Strehl ratio, and a parabolic fit is used to determine the appropriate coefficient correction that maximizes the Strehl ratio. Historic calibrations of the NCPA file in Altair's control loop were done at night on a celestial point source, and used a separate, high-resolution WFS (with its own inherent aberrations not common to either NIRI nor Altair) to measure phase corrections directly. In this paper it is shown that using FPS on a calibration source negates both the need to use costly time on the night sky and the use of separate optical systems (which introduce their own NCPA) for analysis. An increase of 6% in Strehl ratio is achieved (an improvement over current NCPA corrections of 11%), and discussions of future improvements and extensions of the technique is presented. Furthermore, a potentially unknown problem is uncovered in the form of high spatial frequency degradation in the PSF of the calibration source.
13
Asici, Burak. "Long Wavelength Mercury Cadmium Telluride Photodiodes And Focal Plane Arrays." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12606449/index.pdf.
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This thesis reports the fabrication and characterization of long wavelength infrared mercury cadmium telluride (Hg1-xCdxTe) photodiodes and 128x128 focal plane arrays grown on lattice matched cadmium zinc telluride (Cd1-yZnyTe) substrates by metal organic vapor phase epitaxy (MOVPE). The dark current modeling of 33x33 mm2 Hg1-xCdxTe photodiodes has shown the dark current is dominated by trap assisted tunneling under small reverse bias voltages typically used to bias these detectors. The dominant dark current mechanisms under high reverse bias and low forward bias are band&ndashto&ndash
band tunneling and generation&ndash
recombination, respectively. The photodiodes have yielded a peak 77 K detectivity of 3.2x1010 cm&
#8730
Hz/W with a cut-off wavelength (50%) of 10.92 mm. It has also been found that the 1/f noise current of the detectors at 1 Hz is related to the trap-assisted tunneling current through the empirical relation in=&
#945
TAT(ITAT)&
#946
with &
#945
TAT=7.0 x 10-5 and &
#946
=0.65. In the course of the focal plane array (FPA) fabrication process development work, ohmic contact formation on p-type Hg1-xCdxTe and mesa wet etch were studied in detail. Contacts with chromium, gold, platinum and copper on p-type Hg1-xCdxTe resulted in bad ohmic contacts, which did not seem to improve with annealing. On the other hand a HgTe cap layer on p-type Hg1-xCdxTe resulted in good ohmic contact with acceptably low resistance. Among the etchants studied for mesa etching of the diode structures, Br2/HBr solution yielded the best performance. After developing all of the steps of FPA processing, 128x128 Hg1-xCdxTe FPAs were successfully fabricated and tested in a thermal imager. While thermal imaging was performed with the FPAs, high nonuniformity of the material and low R0A product of the pixels did not allow high sensitivity imaging.
14
Ridder, Trent D. "Exploring expanded wavelength regions with solid state focal plane detectors." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289195.
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This dissertation research has focused on the design of two spectroscopic instruments that operate outside of the UV/visible region for the analysis of volatile organic hydrocarbons and hard-to-separate hydrocarbon mixtures. The first design was solid state near infrared spectrometer. The fast acquisition rate of the NIR spectrometer allowed the monitoring of the bromination of 1-hexene. The concentrations of 1-hexene and 1,2-dibromohexane were determined for the reaction using classical least squares. The root mean squared errors of prediction for 1-hexene and 1,2-dibromohexane concentrations were 0.01 and 0.003 M, respectively. This research project also focused on the investigation of the effects of instrumental parameters on partial least squares models by comparing the results obtained from four different spectrometers. The results indicate that instrumental parameters, such as resolution and wavelength coverage, have a larger effect on experimental results than the analysis method (NIR or Raman). The second instrument design investigated here was a vacuum ultraviolet ICP-AES which monitored the 130 to 200 nm wavelength range. Fifteen nonmetals were used to determine the quantitative characteristics of the design. All elements demonstrated detection limits in the ppb range. The most sensitive emission line in this work was the aluminum 167.079 nm line which had a detection limit of 200 ppt. A VUV atomic emission line database was developed to provide an analytical reference for future investigations. The database included the emission lines from 76 elements over the 130 to 195 nm wavelength region. Over 2200 lines were observed and reported. Over 1000 of the lines were previously unreported in the two major existing references for the VUV. This work is the first VUV reference to provide truly comparable intensities for a large number of elements. A GC-VUV-ICP-AES was developed to investigate the potential of VUV-ICP atomic emission spectroscopy to provide both quantitative and qualitative information for mixtures. Chlorine and carbon chromatograms were obtained simultaneously for volatile organic hydrocarbon (VOC) mixtures. The work showed that GC-VUV-ICP-AES has the potential of generating empirical formulas for compounds by simultaneously quantitating each element in the compound and determining their ratios.
15
Hu, Xinda. "Development Of The Depth-Fused Multi-Focal-Plane Display Technology." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/338957.
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Conventional stereoscopic displays present a pair of stereoscopic images on a single and fixed image plane. In consequence, these displays lack the capability of correctly rendering focus cues (i.e. accommodation and retinal blur) and may induce the discrepancy between accommodation and convergence. A number of visual artifacts associated with incorrect focus cues in stereoscopic displays have been reported, limiting the applicability of these displays for demanding applications and daily usage. Depth-fused multi-focal-plane display was proposed to create a fixed-viewpoint volumetric display capable of rendering correct or nearly-correct focus cues in a stereoscopic display through a small number of discretely placed focal planes. It effectively addresses the negative effects of conventional stereoscopic displays on depth perception accuracy and visual fatigue. In this dissertation, the fundamental design methods and considerations of depth-fused displays were refined and extended based on previous works and a high-resolution optical see-through multi-focal-plane head-mounted display enabled by state-of-the-art freeform optics was developed. The prototype system is capable of rendering nearly-correct focus cues for a large volume of 3D space extending into a depth range from 0 to 3 diopters at flicker-free speed. By incorporating freeform optics, the prototype not only achieves high quality imagery across a large 3D volume for the virtual display path but it also maintains better than 0.5 arcminutes visual resolution of the see-through view. The optical design, implementation and experimental validation of the display are presented and discussed in detail.
16
Wakefield, Amory. "Influences on post-correction nonuniformity of infrared focal plane arrays." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/42721.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (leaves 75-77).
by Amory Wakefield.
M.Eng.
17
Xie, Chengzhi. "A novel monolithic focal plane array for mid-IR imaging." Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8106/.
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The use of Mid-infrared (mid-IR) imagers has great potential for a number of applications in gas sensing and medical diagnostics, but so far for many of those non-defence fields it has been significantly limited by their high price tag. One of the reasons behind the great cost of mid-IR imagers is that most of them need to operate at cryogenic temperatures. Thanks to more than half a century of research, state-of-the-art mid-IR photodetectors have finally achieved premium detection performance without the need for cryogenic cooling. Some of them have even demonstrated very promising results, suggesting room temperature operation is on the horizon. As a result, the cost associated with cooling equipment has been significantly suppressed. However, most mid-IR imagers are still based on hybrid technologies needing a great number of die-level process steps and being prone to connection failure during thermal cycles. The high manufacturing cost this entails is also preventing a wider diffusion of mid-IR imagers. Currently, there is still a lack of an effective monolithic approach able to achieve low-cost mass production of mid-IR imagers in the same way as monolithic integration has been widely used for imagers working at visible wavelengths. This thesis presents a novel monolithic approach for making mid-IR imagers based on co-integration of mid-IR photodetectors with GaAs-based MESFETs on the same chip. The initial focus of the project was the development of the fabrication steps for delivery of prototype devices. In order to achieve monolithic fabrication of pixel devices made in either indium antimonide (InSb) or indium arsenide antimonide (InAsSb) on a gallium arsenide (GaAs) substrate, various highly controllable etch processes, both wet and dry etch based, were established for distinct material layers. Moreover, low temperature annealed Ohmic contacts to both antimonide-based materials and GaAs were used. The processing temperatures used never exceeded 180˚C, preventing degradation of photodetector performance after fabrication of transistors, thus avoiding well-known thermal issues of InSb fabrication. Furthermore, an intermediate step based on polyimide was developed to provide a smoothing section between the lower MESFET and upper photodetector regions of the pixel device. The polyimide planarisation enabled metal interconnects between the fabricated devices regardless of the considerable etch step ( > 6 µm) created after multiple mesa etches. Detailed electrical and optical measurements demonstrated that the devices were sensitive to mid-IR radiation in the 3 to 5 µm range at room temperature, and that each pixel could be isolated from its contacts by switching off the co-integrated MESFET. Following the newly developed fabrication flow, InSb-based mid-IR imaging arrays (in two sizes, 4×4 and 8×8) are presented here for the first time, with pixel addressing achieved by monolithically integrated GaAs MESFETs. By demonstrating real-time imaging results obtained from these array devices at room temperature, implementation of a new type of monolithic focal plane array for mid-IR imaging has been confirmed. The device is suitable for further scaling (up to 64×64 pixel and beyond) and potential commercialisation. More importantly, the monolithic approach developed in this work is very flexible, as a number of III-V materials with mid-IR detecting capabilities can be grown on GaAs substrates, meaning alternative semiconductor layer structures could also be investigated in the near future.
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Keasler, Craig Alan. "Advanced numerical modeling and characterization of infrared focal plane arrays." Thesis, Boston University, 2012. https://hdl.handle.net/2144/31575.
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Thesis (Ph.D.)--Boston UniversityPLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
Mercury cadmium telluride (HgCdTe) is the detector material of choice for high performance infrared (IR) focal plane arrays (FPAs). Unique among semiconductor materials, HgCdTe features a widely tunable, direct bandgap from the ultraviolet to very long wavelength IR, lattice matched substrates, excellent quality epitaxial layers, and long minority carrier lifetimes. The requirements for better HgCdTe device performance are driving advancements in numerical modeling and characterization. In particular, numerical models and physical device simulations have become indispensable tools to understand the physics and optimize the operation of complex HgCdTe pixel arrays. Existing limitations in current numerical models prevent the study of new, higher performance pixel designs with much higher resolutions necessitating smaller pixels and novel structures that take advantage of the wave nature of light. Additionally, the costs associated with larger FPAs are driving the development of non-destructive testing methods during production and assembly. This thesis describes the contributions I have made to both the development of novel models for physical device simulation and to innovative characterization techniques for FPAs with read-out integrated circuits (ROICs). I have developed an integrated model for simulating the electromagnetic and electrical response of pixel arrays. I describe the results I have obtained applying the newly developed simulation approach to study planar detectors, small pixel mesa-type detectors, and photon trapping (PT) structures. I have examined the effect that reducing pixel pitch has on performance and the benefits of detectors with PT structures. The outcome of the work on the PT structured detector has led to the development of a new detector by BAE Systems, Inc. I will also present work towards the development of a temporary hybridization method. HgCdTe-based detectors are hybrid structures where HgCdTe FPAs are indium bump bonded to silicon ROICs. FPAs are tested by permanently hybridizing an array to a ROIC and both must be discarded if an FPA fails. The latest generation arrays are larger than 7 cm square and the corresponding ROICs are increasing in cost and complexity. Using the temporary hybridization technique I have evaluated, the array and ROIC can be nondestructively separated in case of a test failure for reuse.
2031-01-01
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Martinache, Frantz, Nemanja Jovanovic, and Olivier Guyon. "Closed-loop focal plane wavefront control with the SCExAO instrument." EDP SCIENCES S A, 2016. http://hdl.handle.net/10150/622158.
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Aims. This article describes the implementation of a focal plane based wavefront control loop on the high-contrast imaging instrument SCExAO (Subaru Coronagraphic Extreme Adaptive Optics). The sensor relies on the Fourier analysis of conventional focal-plane images acquired after an asymmetric mask is introduced in the pupil of the instrument. Methods. This absolute sensor is used here in a closed-loop to compensate for the non-common path errors that normally affects any imaging system relying on an upstream adaptive optics system. This specific implementation was used to control low-order modes corresponding to eight zernike modes (from focus to spherical). Results. This loop was successfully run on-sky at the Subaru Telescope and is used to offset the SCExAO deformable mirror shape used as a zero-point by the high-order wavefront sensor. The paper details the range of errors this wavefront-sensing approach can operate within and explores the impact of saturation of the data and how it can be bypassed, at a cost in performance. Conclusions. Beyond this application, because of its low hardware impact, the asymmetric pupil Fourier wavefront sensor (APF-WFS) can easily be ported in a wide variety of wavefront sensing contexts, for ground-as well space-borne telescopes, and for telescope pupils that can be continuous, segmented or even sparse. The technique is powerful because it measures the wavefront where it really matters, at the level of the science detector.
20
Zhang, Junchao, Haibo Luo, Rongguang Liang, Wei Zhou, Bin Hui, and Zheng Chang. "PCA-based denoising method for division of focal plane polarimeters." OPTICAL SOC AMER, 2017. http://hdl.handle.net/10150/623248.
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Division of focal plane (DoFP) polarimeters are composed of interlaced linear polarizers overlaid upon a focal plane array sensor. The interpolation is essential to reconstruct polarization information. However, current interpolation methods are based on the unrealistic assumption of noise-free images. Thus, it is advantageous to carry out denoising before interpolation. In this paper, we propose a principle component analysis (PCA) based denoising method, which works directly on DoFP images. Both simulated and real DoFP images are used to evaluate the denoising performance. Experimental results show that the proposed method can effectively suppress noise while preserving edges. (C) 2017 Optical Society of America
21
Arslan, Yetkin. "Large Format Dual-band Quantum Well Infrared Photodetector Focal Plane Arrays." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610936/index.pdf.
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Quantum Well Infrared Photodetectors (QWIPs) are strong competitors to other detector technologies for future third generation thermal imagers. QWIPs have inherent advantages of mature III-V material system and well settled fabrication technology, as well as narrow band photo-response which is an important property facilitating the development of dual-band imagers with low crosstalk. This thesis focuses on the development of long/mid wavelength dual band QWIP focal plane arrays (FPAs) based on the AlGaAs/GaAs material system.
Apart from traditional single band QWIPs, the dual-band operation is achieved by proper design of a bias tunable quantum well structure which has two responsivity peaks at 4.8 and 8.4 um for midwave infrared (MWIR) and longwave infrared (LWIR) atmospheric windows, respectively. The fabricated large format (640x512) FPA has MWIR and LWIR cut-off wavelengths of 5.1 and 8.9 um, and it provides noise equivalent temperature differences (NETDs) of ~ 20 and 32 mK (f/1.5 at 65 K) in these bands, respectively. The employed bias tuning approach for the dual-band operation requires the same fabrication steps established for single band QWIP FPAs, which is an important advantage of the selected method resulting in high-yield, high-uniformity and low-cost. Results are encouraging for fabrication of low cost, large format, and high performance dual band FPAs, making QWIP a stronger candidate in the competition for third generation thermal imagers
22
Álvarez, Pastor José Manuel. "Focal plane detectors of a Laue lens telescope for Nuclear Astrophysics." Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/83940.
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centenares de keV hasta unos pocos MeV), presenta un extraordinario potencial para comprender
los procesos más extremos que tienen lugar en el Universo, como las explosiones estelares o los
aceleradores de partículas. No obstante, a pesar de los enormes esfuerzos realizados por los
observatorios de rayos gamma (en el pasado y en la actualidad), se requiere una mejora en la
sensibilidad instrumental para aprovechar el enorme potencial científico contenido en este rango
energético.
Durante las dos últimas décadas se han buscado formas de mejorar la sensibilidad de los
instrumentos, incrementando la eficiencia de los detectores y reduciendo el ruido instrumental
(mediante sofisticados mecanismos de blindaje y técnicas de análisis). Con este objetivo, un enorme
esfuerzo en innovación instrumental (construcción de prototipos y estudios numéricos) está siendo
realizado por una comunidad creciente de científicos que se enfrentan al reto de preparar la próxima
generación de telescopios de rayos gamma. En particular, son especialmente notables los avances
logrados en los últimos años en el campo de la focalización de rayos gamma mediante lentes de
difracción. Conceptualmente, una lente de rayos gamma reduciría drásticamente el ruido
instrumental ya que concentra los fotones en un detector de pequeñas dimensiones (el ruido es
proporcional al volumen del instrumento). Una lente de difracción, para observaciones en astrofísica
nuclear, no es sólo un concepto teórico, sino una realidad, gracias principalmente al proyecto
CLAIRE. Asimismo, el desarrollo de la tecnología para la focalización de rayos gamma ha
incentivado el desarrollo de las diferentes tecnologías de detección. Un detector apropiado para el
plano focal de una lente gamma, debe disponer de capacidad de imagen, proporcionar
espectroscopia de alta resolución y medir la polarización de los fotones incidentes.
El trabajo presentado en esta tesis comprende tanto la óptica de focalización como el detector del
plano focal. Con respecto a la óptica, se presenta el ensayo realizado con el prototipo CLAIRE,
mediante el cual se ha confirmado los principios de una lente de difracción. En cuanto al plano
focal, esta investigación se ha desarrollado principalmente en el marco de estudio de las misiones
espaciales GRI (2007) y DUAL (2010), propuestas a la ESA dentro del programa “Cosmic Vision
2015-2025”. En el marco de la misión GRI, se presenta una configuración para el detector del plano
focal basado en detectores pixelados de Cd(Zn)Te, al tiempo que se investiga y desarrolla un primer
prototipo de detector pixelado de CdTe. Cabe destacar que el sistema de detección propuesto fue
registrado con éxito mediante una patente europea, y está siendo desarrollado para su aplicación en
medicina nuclear. En relación a la propuesta DUAL, se presenta un estudio del ruido instrumental
obtenido mediante simulaciones numéricas con el fin de precisar la sensibilidad del instrumento
(basado en detectores de Germanio) propuesto en esta misión. Más allá de las tecnología
consideradas en GRI y DUAL, una amplia variedad de detectores pueden ser explorados, bien para
el plano focal de una lente de difracción o bien como sistemas de detección por sí mismos. En este
sentido, se ha ampliado el espectro de tecnologías y se ha incluido un estudio sobre detectores
basados en xenón líquido.
En esta tesis se ha realizado un trabajo de investigación y desarrollo con tecnologías vanguardistas
propuestas para la próxima generación de telescopios de rayos gamma. Esta instrumentación debe
enfrentarse al reto de alcanzar la sensibilidad requerida para dar respuesta a las cuestiones aun no
resultas por la astrofísica de rayos gamma en el rango de energía de las transiciones nucleares.few MeV) has an extraordinary potential for understanding the evolving and violent Universe. In spite of the strong efforts accomplished by past and current instruments, in order to perform observations in this energy range, an improvement in sensitivity over present technologies is needed to take full advantage of the scientific potential contained in this energy range. In order to achieve higher sensitivities, γ-ray astronomy has been looking over the last decades for new ways to increase the efficiency of its instruments while reducing the background noise. With the objective of reducing or avoiding as much background as possible (through shielding mechanisms and data analysis techniques), a strong effort in innovation and design (build-up of prototypes and numerical simulations studies) is being conducted by a community facing the challenge of preparing the next generation of γ-ray telescopes. In particular, the progress achieved during the last decade on focusing optics based on Laue lenses is especially remarkable. Conceptually, a focusing telescope will reduce drastically the background noise by concentrating γ-rays onto a small size detector. Focusing γ-rays with a Laue lens is not just a theoretical concept, but a reality, mainly thanks to the development of a first prototype of Laue lens for nuclear astrophysics accomplished as part of the CLAIRE project. Moreover, the development of focusing optics during these years has also encouraged the development of new detector technologies. The focal plane detector of a focusing telescope should provide imaging capabilities, perform high-resolution spectroscopy and measure the polarization of the incident photons in order to achieve the ambitious scientific goals. The research presented in this thesis covers both main areas of a γ-rays telescope: focusing optics and focal plane detector. As far as the optics is concerned, a test of the lens CLAIRE was performed in order to confirm the principles of a Laue diffraction lens. Concerning the focal plane detector, theoretical and experimental studies with new detector technologies have been carried out. Our main research has evolved in the framework of two mission concept studies -GRI (2007) and DUAL (2010)- submitted to the ESA Calls for a Medium-size mission opportunity within the Cosmic Vision 2015-2025 program. As far as the GRI mission is concerned, a focal plane detector configuration based on Cd(Zn)Te pixelated detectors is proposed, whilst development and testing of a detector prototype is accomplished. It is noteworthy that the detector configuration was successfully registered under a European Patent and is being considered for applications in the field of nuclear medicine. Regarding the DUAL mission, simulations of the expected space radiation environment and the resulting detector activation were carried out in order to estimate the performances of the all-sky Compton telescope of DUAL (based on Germanium-strip detectors). The results show that DUAL could achieve, after two years of operation, a continuum sensitivity one order of magnitude better than any past and current observatory in the MeV energy range and up to a factor 30 of improvement with its Laue lens. Beyond the detector technology proposed for GRI and DUAL, a wide variety of technologies could be explored for the focal plane of a γ-ray lens mission as well as for a stand-alone detector. In this thesis a focal plane detector based on liquid xenon is also considered. This work faces the challenges of the next generation of γ-ray telescopes, where high performance γ-ray detectors are necessary to achieve the required sensitivity in order to answer several hot scientific topics of Gamma-ray astrophysics in the energy range of nuclear transitions.
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Rabanus, David. "Development of a modular stressed Ge:Ga photoconductor focal plane array prototype." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962396206.
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Fox, Marsha Jane. "Undersampled focal plane detection of imagery from a sparse telescope array." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186175.
Full textAbstract:
For sparsely distributed arrays of optical telescopes operating in phase, large regions of complete attenuation in the modulation transfer function (MTF) result from the spaces between telescopes. These 'holes' in the MTF can be used to advantage to avoid aliasing of high spatial frequency components when the resultant optical image is undersampled by a detector array. The technique for isolating and removing the harmonic components of the sampled image spectrum from the undersampled image has been labeled 'dealiasing'. The result of undersampling the image plane is a reduction in the number of detectors required to image a particular scene by nearly a factor of four. The appropriate conditions for recovering a non-aliased image from the undersampled image focal plane are set by two parameters; the configuration of the pupil, and the detector array sampling rate. The two parameters are coupled, so that the selection of one constrains the allowed values of the other. Errors may be introduced by incorrectly scaling the pupil function to the detector array. Increasing the size of the individual subapertures in the telescope array beyond a prescribed limit also introduces errors that significantly degrade the dealiased result. The latter error is partially mitigated by the associated increase in object information transferred into the image. In this study, an algorithm is formulated to implement the dealiasing technique. The algorithm is demonstrated on point and extended objects using both an image simulation environment and a laboratory breadboard. The robustness of the algorithm to sources of error and the introduction of noise are measured. Quantitative metrics and visual assessment of image quality are used to evaluate the results. The CLEAN algorithm, a method to interpolate between the peaks of the image spectrum of the sparse telescope array is implemented. This enhancement to image quality is useful when demonstrating the concept on detailed, high resolution objects. Finally, a concept for enhancing the image quality of a sparse telescope array is presented. The technique combines imagery of two wavelengths, co-focal on the detector array. One image is of high resolution, undersampled, and dealiased. The second image is Nyquist-sampled but of low resolution. This technique significantly improves on the quality of sparse array imagery obtained at a single wavelength.
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Graeve, Thorsten. "Characterization and modeling of high speed, high resolution focal plane arrays." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186737.
Full textAbstract:
The work presented in this dissertation examines the characterization and modeling of visible charge-coupled devices (CCDs). A theoretical model is discussed that represents the parallel clock register of a CCD as a lumped system of discrete resistances and capacitances. This model can be used to simulate the electrical performance of the clock register. From the simulation results the clock pulse degradation in the lossy transmission line model of the clock electrode can be determined. An upper limit is found to the parallel clock frequency at which reasonable pulse shapes are preserved. In addition, the model is used to find the current flow and the power dissipation within the clock electrodes. Through simulations, the total power dissipation on a high-speed, high-resolution CCD can be calculated and compared to theoretical values obtained from a conventional model. The experimental part of this dissertation covers the theory and application of test methodology for the characterization of high-speed, high-resolution CCDs. Both standard and novel techniques for CCD evaluation are discussed, covering all standard figures-of-merit such as read noise, full-well capacity, dynamic range, conversion gain, charge transfer efficiency, MTF, quantum efficiency, non-uniformity, dark current, linearity and lag. This chapter is followed by a discussion of the test camera hardware and software that is used to develop characterization techniques and apply them to specific devices. Finally, the characterization results from applying these techniques to the English Electric Valve (EEV) CCD13 are presented. This device is a 512 by 512 pixel, 8-output, three-phase, full-frame CCD that was designed for readout periods of less than 2 ms. It has been characterized at data rates up to 1 MHz, resulting in video acquisition of 128 by 64 pixel subarrays at 100 frames per second. The results show that both experimental characterization and theoretical modeling are two important aspects of CCD evaluation, providing necessary data to customers and valuable feedback to manufacturers.
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Wakui, Elley. "Optimisation and characterisation of the archeops CMB anistrophy experiment focal plane." Thesis, Queen Mary, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419797.
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Weller, Harald. "CMOS monolithic pyroelectric infrared focal plane arrays using PVDF thin films." Thesis, Edinburgh Napier University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323080.
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Juliano, Laura S. (Laura Susan). "Study of scene-based nonuniformity compensation in infrared focal plane arrays." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40186.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (leaves 77-79).
by Laura S. Juliano.
M.Eng.
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Zonca, Andrea. "Advanced modelling and combined data analysis of planck focal plane instruments." Paris 7, 2008. http://www.theses.fr/2008PA077169.
Full textAbstract:
Le sujet principal de mon travail de thèse est le logiciel de modélisation des radiomètres de l'instrument basse fréquence (LFI). LFI est l'un des deux instruments embarqués sur le satellite Planck de l'Agence spatiale européenne pour le mesurage de haute précision des anisotropies du rayonnement fossile. Le modèle logiciel s'appuie sur la réponse en fréquence mesurée des radiomètres éléments sur un simulateur de guide d'ondes analytique dans le but de simuler la réponse en fréquence du LFI canal par canal. Sa mise en œuvre est basée sur QUCS, un simulateur de circuit libre. La bande passante modélisée a montré la bonne cohérence avec les performances mesurées et moins a souffert des effets systématiques, ils sont donc les meilleures estimations disponibles pour la réponse en fréquence des radiomètres. Grâce à la collaboration avec Jean-Michel Lamarre, Instrument Scientist du HFI, l'instrument bolometrique de Planck, l'accent de mor activité a été élargie et a inclus l'étude de la corrélation croisée entre HFI et LFI données, sur deux aspects principaux: le calcul des fonctions de transfert thermique de l'étape à 4K au cours des tests et des simulations. Le 4K étape est un élément clé da la chaîne cryogénique de HFI, et c'est utilisée comme une charge de référence stable par LFI. Le projet des sessions de quick look analysis (QLA) que exploitent données scientifiques et housekeeping de ces deux instruments dans le but d'identifier les effets systématiques. Les sessions reposent sur le logiciel de visualisation de données KST et sont composées d'un ensemble de sessions de base déjà mis en œuvre et testées, permettant par exemple de produire spectra et corrélations croisée et une série de sessions avancées, dédiées à l'étude d'un aspect spécifique, par exemple la corrélation entre canaux de 70 GHz de Ll de 100 GHz de HFIThe main topic of my PhD work is the software modelling of the Low Frequency Instrument (LFI) radiometers. The LFI is one of the two instruments on-board the European Space Agency Planck Mission for high precision measurements of the anisotropies of the Cosmic Microwave Background (CMB). The software model relies on measured frequency response of the LFI radiometers components and on an analytical waveguide simu in order to simulate the LFI bandpasses channel by channel. Its implementation is based on QUCS, an open-source circuit Simulator. Modelled bandpasses showed good consistency with the measured performance and suffered less systematic effects, they are therefore the best estimate available for the radiometers frequency response. Thanks to the collaboration with Jean-Michel Lamarre, HFI Instrument Scientist, the bolometric instrument on-board Planck, the focus my activity was broadened and included the study of cross-correlation between HFI and LFI data, on two main aspects: The computation of the thermal transfer functions of the stage at 4K during tests and from simulations. The 4K stage is a key element the HFI cryogenic chain and it is used as a stable reference load by LFI. The design of quick look analysis sessions exploiting both instruments scientific and housekeeping data in order to identify systematic effects. Sessions relies on the data visualization software KST and consist of a set of already implemented and tested basic sessions allowing for example to produce spectra and cross-correlations, and a set of advanced sessions, dedicated on the study of a specific aspect, for example the correlation between LFI 70 GHz and HFI 100 GHz channels
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Finet, Marc A. "Sensor Hardening Through Translation of the Detector from the Focal Plane." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1343769240.
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Wood, Sean James. "Image quality of optical systems when used with focal plane array detectors." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384898.
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Hartmann, Nicolai. "Coupling of emitters to surface plasmons investigated by back focal plane microscopy." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-164238.
Full textAbstract:
Current efforts in the field of plasmonics towards device integration and miniaturization require detailed knowledge about the coupling between surface plasmons and emitters. In this work coupling between surface plasmon polaritons and different emitter systems has been investigated by the technique of back focal plane imaging. To develop a deeper understanding of the interaction phenomena the studies focused on single emitters in elementary plasmonic configurations that allow for an analytical description.
The first part of the thesis reports on the successful demonstration of surface plasmon polaritons launched by a single dipolar carbon nanotube emitter on a metal thin film after local optical excitation. Leakage radiation microscopy images, recorded in the back focal plane of a microscope objective, could be modeled successfully and contained the propagation length and direction of surface plasmon polaritons. Corresponding real-space images revealed plasmon propagation away from the single dipolar plasmon source. The polarization behavior of surface plasmon polaritons launched by single carbon nanotubes was found to be radial as predicted by theoretical calculations.
Remote excitation of single walled carbon nanotube excitons via propagating surface plasmons is demonstrated in the second part. A scanning aperture probe was used as source for propagating surface plasmons with fine controllability over excitation position and propagation direction. It was raster scanned in close proximity over a single carbon nanotube located on a metal film while recording the emission response from the nanotube. The carbon nanotube showed an emission response while the aperture plasmon source was still far away from the nanotube position. Theoretical modeling of the excited surface plasmon fields confirmed that the nanotube maps the surface plasmons locally with sub-diffraction resolution.
In the last part, radiation channels in the vicinity of a plasmonic nanowire were investigated. Radiation patterns of a coupled system of rare earth nanocrystals and silver nanowires in the back focal plane revealed that the emission in the vicinity of a nanowire can be approximately described by two emission channels that can be calculated analytically: Dipolar emission, also observed in the absence of the nanowire, and leakage radiation from the nanowire. The latter can be calculated using an antenna-resonator model that considers the air-dielectric interface on which the nanowire is deposited and the position of excitation along the nanowire. Fitting of the experimentally observed patterns provides estimates for the branching ratio between the two emission channels and further enable the determination of the plasmon wave-vector supported by the nanowires.
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Fleck, Andre. "Monte Carlo studies of the Jefferson Lab Hall A focal plane polarimeter." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ54706.pdf.
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Berg, Elliott Philip. "High-speed focal plane array camera for mid-infrared impulse photothermal radiometry." Thesis, London South Bank University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367903.
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FERRO, ANDREW F. "DEFECTIVE PIXEL CORRECTION AND RESTORATION IN STARING REMOTE SENSOR FOCAL PLANE ARRAYS." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1132075897.
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Robinson, William Hugh. "Modeling and implementation of an integrated pixel processing tile for focal plane systems." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04072004-180157/unrestricted/robinson%5Fwilliam%5Fh%5F200312%5Fphd.pdf.
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Tumkaya, Umid. "Performance Assesment Of Indium Antimonide Photodetectors On Silicon Substrates." Thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/756403/index.pdf.
Full textAbstract:
In this study, detailed characteristics and performance assessment of 3−
5 µ
m p-i-n InSb photodetectors on Si substrates are reported. The detector epilayers were grown on GaAs coated Si substrates by molecular beam apitaxy (MBE). Both homojunction and single heterojunction (AlInSb/InSb) detector structures were investigated. Arrays of 33x33 µ
m2 detectors were fabricated and flip-chip bonded to a test substrate for detailed electrical and optical characterization. A peak detectivity as high as 1x1010 cmHz1/2/W was achieved with InSb homojunction detectors on Si substrate in spite of the large lattice mismatch between InSb and Si (%19). In both homojunction and single heterojunction structures the differential resistance is significantly degraded by trap assisted tunneling (TAT) under moderately large reverse bias and by ohmic leakage near zero-bias. While the heterojunction structures provide a higher 80 K zero bias differential resistance, the responsivity of this structure is significantly lower than that of homojunction InSb photodiodes. In both homojunction and heterojunction photodetectors, 80K 1/f noise is dominated by TAT processes, and the noise current at 1 Hz follows the empirical relation in= &
#945
TAT(ITAT) &
#946
with &
#945
TAT&
#8764
1.1x10&
#8211
6 and &
#946
&
#8764
0.53.
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Ludick, Daniel Jacobus. "Efficient numerical analysis of focal plane antennas for the SKA and the MeerKAT." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4134.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: The use of Focal Plane Arrays (FPAs) as suitable feed-structures for the Parabolic Dish Reflector antennas that are intended to form a large part of the Square Kilometre Array (SKA) is currently the topic of conversation in various SKA research groups. The simulation of these structures however, relies on intensive computational resources, which can result in very long simulation runtimes - a serious problem for antenna designers. It was the purpose of the research to investigate efficient simulation techniques, based on the Method of Moments (MoM). In this thesis, the reader will be introduced to ways of improving FPA design by using resources such as High Performance Clusters, developing efficient MoM formulations for FPAs such as the Vivaldi antenna array and by developing efficient solution techniques for the resulting MoM equations by using techniques such as the Characteristic Basis Function Method (CBFM). In addition to the above mentioned methods, the concept of distributed computing is explored as a way to further aid the antenna designer in obtaining desired results in a reasonable time and with sufficient accuracy.
AFRIKAANSE OPSOMMING: Die gebruik van Fokus Punt Samestellings (FPS) vir die voer van Paraboliese Skottel Antennas in die Square Kilometer Array (SKA), geniet tans baie aandag in verkeie navorsing-sirkels. Die analise van hierdie samestellings vereis egter intensiewe berekenings-infrastrukture, wat tot lang simulasies kan lei - ’n ernstige probleem vir antenna ontwerpers. Die doel van die skrywer se navorsing was om effektiewe simulasie metodes te ondersoek, gebaseer op die Moment Metode. In hierdie tesis, sal die leser bekendgestel word aan verskeie metodes om die ontwerp van Fokus Punt Samestellings doeltreffend te verrig; nl. die gebruik van Parallel Rekenaar Klusters, die ontwikkeling van effektiewe Moment Metode kode vir samestellings soos die Vivaldi antenna konfigurasie, asook die ontwikkeling van effektiewe oplos-metodes vir die matrikse wat deur die Moment Metode gelewer word, deur die sogenaamde Karakteristieke Basis Funksie Metode (KBFM) te gebruik. Hierby ingesluit word die konsep van verspreide numeriese berekening ondersoek, as ’n manier waarop die antenna ontwerper resultate binne ’n aanvaarbare tyd en akkuraatheid kan verkry.
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Blocher, Garth M. "Development of an Infrared Direct Viewer Based on a MEMS Focal Plane Array." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/901.
Full textAbstract:
"Thermal infrared (IR) imaging systems are widely used in medical, industrial, and defense applications. IR imaging systems utilize a lens to focus IR radiation onto a focal plane array (FPA) of IR detectors, which transduce the IR radiation from the scene into signals that can be further processed. In conventional IR imaging systems, electronic readout integrated circuitry (ROIC) is used to read out the information from the FPA, and computer signal processing allows for an IR image to be displayed on an electronic screen. However, the ROIC decreases the thermal isolation and sensitivity of the IR detectors in the FPA, and the computer processing and electronic display increase the cost, weight, and complexity of the IR imaging system. This thesis focuses on the development of an IR direct viewing system that does not require any ROIC, computer signal processing, or electronic display. This is accomplished through the use of microelectromechanical systems (MEMS) uncooled IR imaging detectors, which consist of arrays of bimaterial thermomechanical cantilever structures that tilt as a function of IR radiation from a scene. Other members of the WPI-ME/CHSLT group have previously shown that an interferometric optical readout mechanism based on digital holography and computer processing can eliminate the need for ROIC and be used to measure the nanometer scale tilt of the structures in a MEMS-based IR imaging system that was found to have a responsivity of 1.5 nm/K. However, these previously demonstrated results required significant computer processing and an electronic display. The hypothesis of the current work is that an optomechanical readout mechanism can be used to realize an IR direct viewer without the use of ROIC, computer signal processing, or an electronic display. Three optical readout mechanisms were identified for transducing the nanometer scale deformations of the MEMS structures in the FPA into a directly observable visible light image. Two of these, one using live holography and the other using Nomarski differential interference contrast (DIC), were based on interferometry, while the third, using reflectometry, was based on geometrical optics. The identified optical readout mechanisms were analytically evaluated based on the performance and perception of the human vision system (HVS), and preliminary experimental results were obtained using optical setups constructed for all three readout mechanisms. Based on the analytical and experimental investigations, reflectometry was selected as the most suitable readout mechanism for a direct viewer. A visible light camera was used with custom software to determine a temperature sensitivity of 137 mK for the reflectometry readout, and thermal images of scenes at human body temperature were demonstrated using limited computer processing. A false color, direct view, live IR imaging system was then demonstrated based on a two color reflectometry readout and the output was characterized with respect to the color differentiation sensitivity of the HVS. The system temperature sensitivity, based on the theoretical color differentiation sensitivity of a human observer, was found to be on the order of 10 K across a measuring range of roughly 400 °C, and objects with a temperature as low as approximately 150 °C were distinguishable. The advantages and limitations of the developed IR imaging system are identified and recommendations for further developments and future work are provided."
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Garrett, John. "A 230 GHz focal plane array using a wide IF bandwidth SIS receiver." Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:d47fbf3b-1cf3-4e58-be97-767b9893066e.
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Superconductor-Insulator-Superconductor (SIS) mixers offer the best noise properties of any heterodyne mixing technique at millimetre wavelengths. In astronomy, they are used for sensitive spectroscopy, which is vital for understanding the properties of the cold interstellar medium, including regions of star formation activity. Modern SIS receivers have noise properties that are ∼3 times the quantum limit, and it is now becoming increasingly difficult to lower the noise properties any further. In this thesis, I investigate two techniques that extend the capability of SIS receivers. The first technique is extending the instantaneous bandwidth of the receivers, i.e., the intermediate frequency bandwidth (IFBW). For spectral line sources, wide IFBW expands the survey depth to allow multiple emission lines to be observed simultaneously. Here, I present a new SIS mixer device at 230 GHz. The planar circuit was minimised to reduce any parasitic capacitances that may limit the IFBW. Experimentally, the device provides excellent noise temperatures down to 36 K and an IFBW extending from approximately 0-11 GHz. Simulation software was developed to better understand the performance of this device, and it suggests that the IFBW can be extended to higher frequencies if the IF measurement chain is upgraded. The second technique that I investigate is increasing the number of receivers in the focal plane of the receiver, i.e., adding more pixels. There are many challenges involved in this task including how to fit multiple receivers into a small space, how to properly cool the receiver, and how to deliver the local-oscillator signal. Here, I present a new 1 Ã 4 focal plane array. This array is acting as a demonstrator for a new array architecture that can be expanded into many more pixels in the future. It uses cascaded waveguide power splitters to divide the local-oscillator signal, and then waveguide directional couplers to combine the LO with the astronomical signals. Finally, I present CO(J=1→0) measurements from 34 galaxies in the 5MUSES survey. These measurements trace the amount of cold molecular gas present in these galaxies. By comparing these measurements to other metrics that trace star formation activity (e.g., infrared luminosity), I was able to form empirical relationships between the observed quantities. I also combined these results with other star formation studies from nearby and high redshift galaxies to form scaling relationships spanning a large fraction of cosmic time.
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Watson, Alexander M. "Fabrication of Micropolarizer and Narrow Band-Pass Pixel Filters for Focal Plane Array." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1324658152.
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Reddy, Praven. "Fixed pattern noise compensation in a mercury cadmium telluride infrared focal plane array." Master's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/22231.
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Bibliography: pages 106-109.This thesis describes techniques for the correction of spatial noise artifacts in a mercury cadmium telluride infrared camera system. The spatial noise artifacts are a result of nonuniformities within the infrared focal plane detector array. The techniques presented dispense with the need for traditional temperature references, and provide nonuniformity compensation by using only the statistics of the moving infrared scene and motion of the camera assembly for calibration. Frame averaging is employed, assuming that all of the detector pixels will eventually be irradiated with the same levels of incident flux after some extended period of time. Using a statistical analysis of the camera image data, the correction coefficients are re-calculated and updated. These techniques also ensure that the calculated coefficients continually track the variations in the dark currents as well as temperature changes within the dewar sensor cooling vessel. These scene-based reference free approaches to the calculation of compensation coefficients in the infrared camera are shown to be successful in compensating for the effects of fixed pattern spatial noise.
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Sargent, Garrett Craig. "A Conditional Generative Adversarial Network Demosaicing Strategy for Division of Focal Plane Polarimeters." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1606050550958383.
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Newman, Kevin, Dan Sirbu, Ruslan Belikov, and Olivier Guyon. "Development of PIAA Complex Mask Coronagraphs for large aperture ground-based telescopes." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622426.
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The Phase Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) is an architecture for directly observing extrasolar planets, and can achieve performance near the theoretical limits for any direct-detection instrument. The PIAACMC architecture includes aspheric PIAA optics, and a complex phase-shifting focal plane mask that provides a pi phase shift to a portion of the on-axis starlight. The phase-shifted starlight is forced to interfere destructively with the un-shifted starlight, causing the starlight to be eliminated, and allowing a region for high-contrast imaging near the star. The PIAACMC architecture can be designed for segmented and obscured apertures, so it is particularly well suited for ground-based observing with the next generation of large telescopes. There will be unique scientific opportunities for directly observing Earth-like planets around nearby low-mass stars. We will discuss design strategies for adapting PIAACMC for the next generation of large ground-based telescopes, and present progress on the development of the focal plane mask technology. We also present simulations of wavefront control with PIAACMC, and suggest directions to apply the coronagraph architecture to future telescopes.
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Qassim, K. A. S. "Optimisation of focal plane arrays for microwave imaging : printed Yagi, dielectric rod and constant width slot antennas are investigated and optimised for close stacking in focal plane arrays intended for microwave imaging." Thesis, University of Bradford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320761.
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Eker, Suleyman Umut. "Single And Dual Band Quantum Well Infrared Photodetector Focal Plane Arrays On Inp Substrates." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611601/index.pdf.
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Excellent uniformity and mature material properties of Quantum Well Infrared Photodetectors (QWIPs) have allowed the realization of large format, low cost staring focal plane arrays (FPAs) in various thermal imaging bands. AlGaAs/InGaAs and AlGaAs/GaAs materials systems have been the standard systems for the construction of mid-wavelength infrared (MWIR) and long-wavelength (LWIR) QWIPs. However AlGaAs/GaAs QWIP FPAs suffer from low quantum and conversion efficiencies under high frame rate (low integration time) and/or low background conditions limiting the application area of standard QWIPs. This thesis focuses on the growth and development of InP based single and dual band QWIP FPAs. We experimentally demonstrate that QWIPs on InP substrates provide important advantages that can be utilized to overcome the bottlenecks of the standard GaAs based QWIP technology.
InP/InGaAs material system is an alternative to AlGaAs/GaAs for LWIR QWIPs. We demonstrate a large format (640x512) LWIR QWIP FPA constructed with strained InP/InGaAs material system. The strain introduced to the structure shifts the cut-off wavelength from ~8.5 to 9.7 µm with lambdap=8.9 µ
m. The FPA fabricated with the 40-well epilayer structure yielded a peak quantum efficiency as high as 12% with a broad spectral response (&
#8710
lambda/lambdap=17%). The peak responsivity of the FPA pixels is larger than 1.4 A/W with conversion efficiency as high as 20% in the bias region where the detectivity is reasonably high (2.6x1010 cmHz1/2/W, f/1.5, 65 K). The FPA providing a background limited performance temperature higher than 65 K (f/1.5) satisfies the requirements of most low integration time/low background applications where AlGaAs/GaAs QWIPs cannot be utilized due to low conversion efficiency and read-out circuit noise limited sensitivity. Noise equivalent temperature differences (NETD) of the FPA are as low as 19 and 40 mK with integration times as short as 1.8 ms and 430 µ
s (f/1.5, 65 K), respectively. We also experimentally demonstrate that the cut-off wavelength of MWIR AlInAs/InGaAs QWIPs can be tuned in a sufficiently large range in the MWIR atmospheric window by only changing the quantum well (QW) width at the lattice matched composition. The cut-off wavelength can be shifted up to ~5.0 µ
m with a QW width of 22 Å
in which case very broad spectral response (&
#8710
lambda/lambdap=~30%) and a reasonably high peak detectivity is achievable leading to a NETD as low as 14 mK (f/2) with 25 µ
m pitch in a 640x512 FPA. The advantages of InP based MWIR and LWIR single band QWIPs were combined by growing and fabricating a mid format (320x256) dual band QWIP FPA. The FPA provided NETD (f/1.5, 65 K, 19 ms) values of 27 mK and 29 mK in the MWIR and LWIR modes with an impressively low DC signal nonuniformity of ~ 4%. The results clearly demonstrate that InP based material systems display high potential for MWIR and LWIR single band and MWIR/LWIR dual band QWIP FPAs needed by third generation thermal imagers by overcoming the limitations of the standard GaAs based QWIPs under high frame rate (low integration time) and/or low background conditions.
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McGhee, Scott K. "Evaluation of an uncooled focal plane array thermal imaging camera for effusion cooling research." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0004/MQ45288.pdf.
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Foley, David Paul. "Low power highly linear CMOS output buffer for low temperature infrared focal plane arrays." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/13228.
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Brettin, Aaron. "Microspherical Photonics for Enhancing Resolution of Optical Microscopy and Sensitivity of Focal Plane Arrays." Thesis, The University of North Carolina at Charlotte, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10979114.
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It is shown that the resolution of virtual images of dye-doped dielectric nanospheres obtained through dielectric microspheres can be increased beyond the classical diffraction limit by decreasing the period of nanoplasmonic array used for localized plasmonic structured illumination of these objects. In addition, it is also shown that post-imaging processing, which represents an intrinsic part of structured illumination microscopy, is not required for achieving the super-resolved images. This observation is interpreted due to the fact that the radiation of objects placed at the surface of nanoplasmonic arrays with sufficiently short periods can be almost completely redirected into folded dispersions of nanoplasmonic array, so that the diffraction orders responsible for super-resolution are more efficiently coupled to dielectric microspherical antenna compared to that for the uncoupled radiative modes.
Focal plane arrays (FPAs) are pixelated arrays of photo detectors which are widely used for imaging. The problem of uncooled mid-wave infrared (MWIR) FPAs is related to their large thermal noise. In this work, it is demonstrated that the surface area and thermal noise of pixels can be reduced without sacrificing their sensitivity by using integration with dielectric microspheres, which can be achieved by a novel method of suction assembly of microspheres in microhole arrays. In addition, it is demonstrated that alternative solution of this problem is offered by integration with microconical light concentrators, which can be fabricated by various well-established technologies including the use of the Nanoscribe. Using a simplified two-dimensional (2D) model, it is studied how the photocurrent depends on the geometrical parameters of microcones and on the angle of incidence.
The photoinduced aggregation of nanoparticles is of interest for material science and nonlinear optics applications. Light-driven assembly of nanoplasmonic particles is observed as an optical memory effect taking place due to the aggregation of 20 nm gold nanoparticles in the illuminated regions of the substrate after full evaporation of the liquid suspension. It is shown that the level of photoexcitation intensity required for observation of this effect is several orders of magnitude smaller compared to that in the previous studies of photoinduced aggregation typically performed using intense laser illumination. It is also demonstrated in a preliminary way that the photoinduced aggregation is facilitated in the spectral range resonant with localized surface plasmon resonances in nanoparticles.
Inverse scattering algorithms are of interest for many applications; however, they are usually based on low refractive index contrast approximations and measuring the phase distributions. In contrast, Globally Convergent Inverse Scattering (GCIS) algorithms in principle should allow phaseless image reconstruction for high refractive index objects. In order to test the operation of GCIS algorithms, high-index (n~2) barium titanate glass microspheres were assembled directly at a silicon chip of a cell phone camera and the scattering patterns resembling the shape of the Airy disks were detected using a set of narrow spectral filters throughout a broad range of wavelengths in the visible regime. The results were found to be in a good agreement with the image calculations and can be used for the object reconstruction based on GCIS algorithms.
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Trichopoulos, Georgios C. "Antennas for Terahertz Applications: Focal Plane Arrays and On-chip Non-contact Measurement Probes." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366232598.
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