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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 39 for “"Diffraction Gratings"”.
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Fabrication of extremely smooth blazed diffraction gratings
High efficiency diffraction gratings are important in a variety of applications, such as optical telecommunications, lithography, and spectroscopy. Special interest has been placed on blazed diffraction gratings for their ability to enhance diffraction intensity at the specular reflection angle off …
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Transmission diffraction gratings for soft x-ray spectroscopy and spatial period division
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982.
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Micro- and nanoscale features of insect cuticle and their impacts on wetting, friction, and optical properties
… microtrichia, nanopillars, sculpticells, or gratings. The adaptive roles of these cuticular architectures have become a recent area of interest, notably to serve as inspiration for the creation of novel materials because they result in desirable functionalities such as anti-wetting, …
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Paviršinių difrakcinių elementų optimizavimas ir formavimas femtosekundiniais UV lazerio impulsais /
… devices in modern science and technology is the diffraction grating. Traditional methods of manufacturing diffraction gratings, such as etching, lithography, and others, face various challenges, including limited design capabilities and high costs. With the advancement of laser technologies and …
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Diffractive electron mirror for use in quantum electron microscopy
… fabricated periodic structures in transmission gratings have long been used to coherently split electrons by means of electron diffraction for applications such as interferometry, holography and imaging. Due to their reliance on transmission through matter, however, these methods are prone to …
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Beetle exoskeletal structure and surfaces determine specialized functions: Two case studies
… the tribological and wettability properties of diffraction gratings present on the outer surfaces of various iridescent ground beetle species, in comparison to their counterparts without diffraction gratings. The diffraction gratings on ground beetles are hypothesized to modify frictional …
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Polarization control and measurement with meta-optics
… optics. In this thesis, we present metasurface diffraction gratings designed to produce arbitrarily specified polarization states on a set of defined diffraction orders, given that the polarization of the incident beam is known. The metasurface diffraction gratings are designed using …
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Dual-layered and wavelength-multiplexed optical barcode for high data storage
… Compared to other existing barcode systems, diffraction gratings are used as core elements in the barcode symbol. As any other barcode system, the novel model requires a source of light, the barcode symbol and photodiode detectors. Theoretical background from optics has been used to design …
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Optical instruments for characterization in the nano-scale
… line spacing errors in X-ray blazed synchrotron diffraction gratings to the Angstrom scale in part two. Quantum dots have long been a reliable label in single-molecule applications due to their brightness and photo-stability. These desirable traits come at a price of a large hydrodynamic size, …
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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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Subsurface two-photon lithography: improvements and applications
… procedure on practical devices, including diffraction gratings. Finally, we share improvements on SCRIBE-written waveguide insertion loss and preliminary data on possible applications. Overall, we detail both improvements to the fundamental process of SCRIBE and a variety of applications …
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Interlaminar deformations on the cylindrical surface of a hole in laminated composites: an experimental study
… scheme was developed to produce high-frequency diffraction gratings on singly-curved surfaces. Two different techniques were developed to interrogate specimen gratings on 25.4 mm (1 in.) diameter holes. Eight thick composite laminates from three material systems were tested in uniaxial …
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Fundamental investigations on periodic nano- and microstructured organic solar cells
… <br>different device architectures based on - diffraction gratings, microprisms and <br>buried nanoelectrodes - are investigated in this thesis. <br> <br>Light trapping with diffraction gratings is reported as a promising approach <br>to increase the light absorption in the photoactive layers …
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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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Theory, Design, and Fabrication of Diffractive Grating Coupler for Slab Waveguide
… based on rigorous analyses.</p> <p>The diffraction gratings are fabricated by recording the interference between two waves in photoresist. The waveguide is fabricated from silicon nitride that is deposited by chemical vapor deposition. The diffraction grating recording assembly is …
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Theory and simulation of subwavelength high contrast gratings and their applications in vertical-cavity surface-emitting laser devices
… the qualities and applications of subwavelength gratings. Subwavelength gratings are diffraction gratings with physical dimensions less than the wavelength of incident light. It has been found that by tailoring specific dimension parameters, a number of different reflection profiles can be …
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A systematic study of ion-induced nanopatterning on photonic crystal-based label-free optical biosensor
… periodically-structured dielectric material with diffraction gratings engineered on the surface that can control light propagation through its depth. PC enables resonance of a certain wavelength of light, leading to a significant increase in the intensity of light reflected off the surface, and …
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Diffractive gratings in high-precision interferometry for gravitational wave detection
… seismic, thermal and quantum among other noises. Diffraction gratings have been proposed in all reflective configurations as core optical elements in future detectors. In this thesis phase changes are shown to occur due to lateral displacement of diffractive optics. These couple noise from …
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The design and construction of a photoelectric spectrophotometer for analytical research
… of the Wadsworth mounting for concave reflection diffraction gratings;Upon calibration of the monochromator using a helium spectrum tube as a light source, the wave length scale was found to be linear;Seven separate amplifiers were constructed, of which one was finally used. It suffered less from …
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Enhancement of Light Absorption Efficiency of Solar Cell Using Dual
… research we study the effect of adding a single diffraction grating on top of a solar cell. We simulated the square diffraction grating, as well as triangular diffraction grating. The single square grating showed more favorable results, achieved 330% power improvement compared to 270% power …
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