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 32 for “"Optical-losses"”.
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Cold-cavity measurement of excess optical loss in oxide-confined vertical cavity surface emitting lasers
… requires a quantitative knowledge of the cavity optical losses. A generalized method using sub-threshold spectral measurements matched to model calculations is demonstrated to determine optical loss in microcavity lasers. Cold-cavity spectral characteristics are used to extract the size dependent …
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ADPATIVE MODE MATCHING UPGRADE FOR ADVANCED LIGO
… reducing technologies that are sensitive to optical losses generated by optical cavity mode mismatch. Optical losses due to mode mismatched Fabry-P´erot optical cavities can be reduced by the use of adaptive optics, wavefront sensors, and feedback control loops. Advanced LIGO currently uses …
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Efficiency Improvement of Cross-Compound Parabolic Concentrator for Silicon and Dye-sensitised Solar Cells
… above the receiver edges by 2 mm to reduce optical losses. A series-connected configuration of nine CCPC-integrated silicon cells was tested for building-integrated applications. This configuration was then examined under light exposure to evaluate optical performance; the results indicate …
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Loss analysis of the power conversion efficiency of organic bulk heterojunction solar cells
… solar cells are analyzed. The electrical and optical losses are investigated for one representative material combination using two models for the bulk heterojunction solar cells. These models allow the simulation of current-voltage characteristics of the solar cells. The deficiencies of the …
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Rare-earth doped aluminum oxide lasers for silicon photonics
… of 0.3 nm over a 1 [mu]m2 area, background optical losses as low as 0.1 dB/cm were obtained for undoped films. The development of active photonics components has been realized by use of rare-earth metals as dopants. By co-sputtering aluminum and erbium targets, Er3+ dopants at concentrations …
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Sapphire fiber in optical sensors
The physical and optical properties of sapphire fiber has been investigated in an effort to create a high temperature optical fiber sensor. Sapphire fiber demonstrates high optical attenuation. This attenuation is very sensitive to injection conditions, and roughly proportional to the cube of the …
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Fiber Optic Pressure Sensor Fabrication Using MEMS Technology
… providing low temperature fabrication of optical pressure sensor heads that can operate at high temperature. Fused silica ferrules and fused silica diaphragms are chosen to reduce the temperature dependence. The fused silica diaphragms have been micro-machined using wet chemical etching in …
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Plasmonic devices based on transparent conducting oxides for near infrared applications
… plasmonics and nanophotonics that have enabled optical devices with unprecedented functionalities. Even though remarkable demonstration of at photonic devices has been reported, constituent materials are limited to the noble metals such as gold (Au) and silver (Ag) due to their abundance of free …
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Broadband High Efficiency Fractal-Like and Diverse Geometry Silicon Nanowire Arrays for Photovoltaic Applications
… because of many factors especially the high optical losses. To enhance conversion efficiency, numerous techniques have been proposed to reduce the optical losses and to enhance the absorption of light in thin film PVSC. One promising technique is the nanowire (NW) arrays in general and the …
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Optical fiber temperature sensor based on fiber bragg grating
It is important to study optical fiber temperature sensor based on fiber Bragg Grating. The Fiber Bragg grating sensors can offer highly sensitive, cost effective solutions for optical sensing. While fiber Bragg gratings have been implemented in various sensing applications over the past few …
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Wavefront modelling and sensing for advanced gravitational wave detectors
… was subsequently followed up by observations by optical and radio astronomers — the first time an astrophysical event was observed by two completely separate astrophysical signals. This marked the beginning of multi-messenger astronomy. Since then 90 astrophysical events have been observed using …
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Thermal and spectral effects in intracavity Raman lasers
… lasers, the interactions between the various optical fields are complex, and must be understood in order to realise efficient, high power operation. This thesis presents a detailed investigation of thermal and spectral effects in CW intracavity Raman lasers. A disk geometry was used to reduce …
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Integrated Inp Photonic Switches
… switches are becoming key components in advanced optical networks because of the large variety of applications that they can perform. One of the key advantages of photonic switches is that they redirect or convert light without having to make any optical to electronic conversions and vice versa, …
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Fabrication and light management of microscale solar cells
… active material consumption. The inherent low optical absorption of these ultrathin devices can be effectively improved by either creating nanocone structures on the device surface that elongate the photon propagation path within the cell, or converting the polymer waveguide to a luminescent …
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Quantum noise reduction using squeezed states in LIGO
… to the level of squeezing observed, including optical losses and fluctuations of the squeezing angle. The lessons learned should allow for responsible planning to implement squeezing in Advanced LIGO, either as an alternative to high power operation or an early upgrade to improve the …
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Development of solar thermophotovoltaic systems = Desarrollo de sistemas termofotovoltaicos solares
… which contemplates (among other things) possible optical losses. The model shows that efficiencies above 30% and electric power densities above 50 W/cm2 are achievable. This requires high solar concentration (above 1000 suns) and a method to enhance the energy transfer from the emitter to the …
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Novel rare-earth-doped planar waveguide lasers
… and the resulting guides are shown to have optical losses of < 0.4 dB/cm. Direct UV writing is utilised to fabricate multiple channel sources on this buried platform, and absorbed pump power thresholds as low as 3 mW are demonstrated. These structures offer a new and versatile route to the …
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Energy transfer between surface plasmon polariton modes with hybrid photorefractive liquid crystal cells
… photorefractive effects are generated through optically controlling the conductivity of a ~100nm photoconducting poly-N-vinyl-carboxyl (PVK) layer. Therefore, when a potential is applied across the cell, the liquid crystal alignment and the SPP wavevector is able to be controlled with light. …
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Polymer waveguide based optical interconnects for high-speed on-board communications
… and the potential performance advantages of optical interconnections. This thesis presents the work to address the bandwidth bottleneck by developing high-bandwidth multimode polymer waveguides. The use of multimode waveguides provides relaxed alignment tolerances enabling low-cost assembly …
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Interfacial engineering and alternative device architectures for perovskite photovoltaics
… efficiency perovskite PV devices by mitigating optical losses. In this thesis, ABC perovskite solar cells were developed using various microfabrication and thin film deposition techniques. Complementary interface formation processes are critical in ABC architectures because the n-type and p-type …
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