Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 36 for “"diffraction efficiency"”.
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Characterization of polygrama green photopolymer for Compact Optoelectronic Integrated Neural (COIN) coprocessor applications
… processors as we look at ways to increase the diffraction efficiency. The focus of this research was to optically characterize Polygrama Green, a photopolymer that is sensitive to green light (514 nm). We were able to plot diffraction efficiency versus the exposure energy density for a series …
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Properties and applications of the photorefractive material Ce:KNSBN
… with those of Cu:KNSBN crystal.<br/><br/>The diffraction efficiency from the CeiKNSBN crystal is affected by the applied electric field. The applied field increases the response rate of the grating formation and enhances the diffraction efficiency. There exists an optimum applied field and …
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Fabrication of critical-angle transmission gratings for high efficiency x-ray spectroscopy
Diffraction gratings are fundamental optical elements that separate incident light into its constituent wavelength components. This dispersive feature of diffraction gratings has been broadly utilized in many applications including spectroscopy, microscopy, and interferometry. As high-energy …
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Design and Application of Waveguide Holographic Optical Elements
… can be deposited on various substrates; high diffraction efficiency, high transparency, low scatter, the ability to multiplex multiple holograms in the same element, and the potential for mass production by using replication methods. A waveguide HOE is an element that couples light into/out of …
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An Investigation into full color Edge-lit Holographic Optical Elements
… silver halide and photopolymer materials create diffraction structures that have significant impact on effective recording performance. Typical off-axis holographic recording regimes as well as holographic directional diffusers are analyzed to establish a performance baseline for comparison of …
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Planetary Systems in Polarized Light: Debris Disk Observations and Instrumentation
… characterization and testing of a new type of diffraction grating, called a polarization grating, that we plan to use for future observations of exoplanet atmospheres. The Gemini Planet Imager is a high-contrast imager that includes a polarimetry mode designed to image circumstellar disks. Here …
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Solution-Processed ZnO Nanoparticles for Optically Addressed Spatial Light Modulators and Other Applications
… of ZnO NP-based OASLMs was conducted in terms of diffraction efficiency and response speed, which are two key factors limiting the development of ZnO NP-based OASLMs. The diffraction efficiency was improved by pinpointing the optimum parameters of the driving signal such as waveform, amplitude and …
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Dynamically programmable surfaces for high-speed optical modulation and detection
… microcavity designs can enable high-speed, high diffraction efficiency SLMs with standard-CMOS-compatible driving voltages. An electro-optic material, graphene, is also investigated in detail. A graphene carrier density spatiotemporal modulation technique is proposed and experimentally validated. …
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Phase optimised general error diffusion for diffractive optical component design
… to operate in the Fresnel region with high diffraction efficiency and Signal-to-Noise Ratio (SNR). A number of different target reconstructions are simulated to determine validity and performance of the algorithm. Diffractive optical elements are fabricated to verify performance and a free …
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Energy transfer between surface plasmon polariton modes with hybrid photorefractive liquid crystal cells
… maximise the energy transfer by examining the diffraction efficiency dependence of each variable of the system. The maximum energy transfer observed is 25.3±2.3% for a 1.05eV SPP from a 4µm grating. With the assistance of a numerical simulation of our system we present a series of qualitative …
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Characterisation of grating properties for MOTs at multiple wavelengths and laser cooling Rb on the 5S1/2 - 6P3/2 transition at 420nm
… trap (MOT) utilizing a reflective diffraction grating, a 780nm and a 420nm laser. Taking advantage of the narrower line width of the 6P3/2 state, 420nm lasers can theoretically make a factor of 10 colder MOT than those using 780nm ones based on the Doppler limit. However, …
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Development of Optoelectronic Devices and Computational Tools for the Production and Manipulation of Heavy Rydberg Systems
… modulator is presented which achieves a maximum diffraction efficiency of 54 % at 200 MHz, using a commercial modulator. A novel design is presented for a highly sensitive optical spectrum analyzer for displaying laser mode structure in real time. Utilizing programmable microcontrollers to read …
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Evaluation of spatial-spectral filtering in non-paraxial volume holographic imaging systems
… relationship between the angle of incidence and diffraction efficiency are invesitgated for wavelength-detuned multiplex holograms to establish the limits of the narrow bandwidth lateral field of view. The depth selectivity of the microscope with a volume hologram pupil is also measured and found …
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Advanced Computational Holography for Perceptual Enhancement and Application in HUDs
… computational grid size, which markedly improves efficiency compared with conventional direct expansion, reducing the computational time by 39% for a 3×3 configuration and 59% for a 5×5 subpixel lattice. Furthermore, the zero-order contribution is analysed and effectively suppressed. In parallel, …
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Theoretical Study of Laser Beam Quality and Pulse Shaping by Volume Bragg Gratings
… coupled wave equations. The analytic theory of diffraction efficiency of a CBG with constant chirp and approximate theory of time delay dispersion are presented. Based on those, we performed comparison of the approximate analytic results with the exact numeric coupled-wave modeling. We also …
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Propagation Effect In Inhomogeneous Media, Including Media With Light-induced And Fixed Gratings
… This transmission hologram demonstrates high diffraction efficiency and low sensitivity to polarization and hologram strength. The other is a reflection hologram with two crossed-gratings. It features good angular selectivity in comparison with the poor angular selectivity of conventional …
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Dynamic holography in semiconductors and biomedical optics
… trade-off between dynamic holographic speed and diffraction efficiency. For instance, photorefractive crystals and polymers can have high efficiencies, but operate at low speeds. Conversely, photorefractive quantum-well devices have high speed, but suffer from low diffraction efficiencies.</p> …
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Holographic laser resonators
… hole burns a grating into the gain. The diffraction efficiency of such gain-gratings is studied both theoretically and experimentally and it is shown that, due to the stored inversion, CW phase-conjugate reflectivities of greater than 100 can be achieved in Nd:YVO<sub>4</sub>. Using this …
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Real-time optical intensity correlation using photorefractive BSO
… bias on the optimum fringe velocity and on the diffraction efficiency are studied.<br/><br/>To overcome the inherent drawback of low discrimination of intensity correlation in optical pattern recognition, real-time edge-enhanced intensity correlation is achieved by means of nonlinear holographic …
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Investigating the operating mechanism of a diffraction based biosensor
… determining the mechanism of signal change for a diffraction-based sensor (DBS) system. The DBS detects analyte-binding events by monitoring the change in diffraction efficiency that takes place when analyte molecules adsorb to target molecules that have been patterned onto a surface. The exact …
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