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 20 for “"Continuous-wave laser"”.
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Laboratory investigation of low-density plasmas by continuous-wave laser scattering.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Geology and Geophysics, 1968.
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High-power diode-pumped ytterbium-doped fibre-laser
… done on double cladding ytterbium-doped fibre lasers. The two main subjects developed were the study of an efficient compact-launching system, and the operation of the double cladding compact fibre as a continuous-wave laser and a Q-switched laser. During this work, highly efficient side …
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Generation of fiber-coupled, nondegenerate, polarization-entangled photons for quantum communication
… downconversion of pump photons from a 532 nm continuous-wave laser to generate 798 nm signal and 1.6 tim idler photon pairs in periodically-poled, congruent lithium niobate (PPLN). Difference frequency generation of 798 nm is used for characterizing PPLN, including phase matching bandwidth and …
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External cavity laser label-free biosensor
… reflector as a mirror of an external cavity laser, we demonstrate a new type of label-free optical biosensor that achieves a high quality factor through the process of stimulated emission, while at the same time providing high sensitivity, large dynamic range and simple detection …
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Optically nonlinear spatial and spectral processes in semiconductor microcavities
… tlmat resonant injection of polaritons nsing a continuous wave laser allows the rnicrocavity to operate as an optical parametric oscillator. A full study of the recovery dynanucs of a transiently destabilized nucrocavity optical parametric oscillator is made in this thesis. Destabilization was …
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Fabrication and applications of fibre Bragg gratings
… or without hydrogen loading, and with varying laser power levels are explored. Three new techniques for fabricating chirped gratings are presented. Beams with dissimilar wavefront curvatures are interfered to give chirped gratings. With the same aim techniques of writing gratings on tapered …
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Design and development of distributed feedback transistor lasers
The transistor laser is a unique three-port device that operates simultaneously as a transistor and a laser. With quantum wells incorporated in the base regions of heterojunction bipolar transistors, the transistor laser possesses advantageous characteristics of fast base spontaneous carrier …
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Optical signal generation, stabilization, and manipulation in broadband silicon photonics
… back-end deposition process, CMOS-compatible lasers are developed using aluminum oxide as the host medium. First, a low temperature deposition process is detailed, and erbium-based lasers are demonstrated in the C-band. Then, thulium is studied and characterized as a dopant for applications at …
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Ultrasound and photoacoustic imaging to guide and monitor photothermal therapy
… used in conjunction with matching a continuous wave laser, make photothermal therapy both noninvasive and tumor-specific. However, to become clinically relevant, there is a need to develop an imaging technique to identify tissue composition and to detect the presence of photoabsorbers …
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Design method for ultimate efficiency in linear-cavity continuous-wave lasers using distributed-feedback
… method for the design of linear-cavity continuous-wave laser cavitiesthat guarantees the ultimate efficiency is developed, theoretically studied and experimentally verified. Opposed to the earlier methods, which optimise the parameters of a priori defined cavity, the developed method …
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Surface modification of ceramic and metallic alloy substrates by laser raster-scanning
This work describes the feasibility of continuous wave laser-raster scanprocessing under controlled atmospheric conditions as employed in three distinct surface modification processes: (a) surface roughness reduction of indirect-Selective Laser Sintered 420 martensitic stainless steel–40 wt. % …
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Transition to turbulence and relaminarization of pulsatile pipe flows
… in a refractive index matching setup by using a continuous wave laser and a high-frame-rate digital camera. The position of the piston was continuously recorded by a laser proximity sensor. Different experiments were carried out with Reynolds numbers in the range of 535 4825 and Womersley numbers …
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Dynamic Acoustic Control of Semiconductor Quantum Dot-Based Devices for Quantum Light Generation
… photon chains by resonant scattering of a laser field on a single charged particle in a cavity-enhanced quantum dot. The charge has an associated spin that can determine the time bin of a photon, allowing for information encoding in this degree of freedom. We demonstrate coherent operations …
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Estimating regional nitrous oxide emissions using isotopic ratio observations and a Bayesian inverse framework
… emissions estimates can be reduced in areas with continuous monitoring of N₂O mole fraction and site-specific isotopic ratios. Due to unique heavy-atom (15N and 18O) isotopic substitutions made by different N₂O sources, the measurement of N₂O isotopic ratios in ambient air can help identify the …
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High speed mask-less laser-controlled precision micro-additive manufacture
… has been developed. The technique was based on laser-induced chemical vapour deposition. The novelty in the technique was the usage of pulsed ultrafast lasers instead of continuous wave lasers in pyrolytic dissociation of the chemical precursor. The motivation of the study was that (1) ultrafast …
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Laser diagnostics of soot in hydrocarbon diffusion flames
Driven by the demand for soot-free combustion, laser-based diagnostic techniques on soot have been developing since the late 1980s. One of these techniques is line-of- sight extinction, which is a fast, low-cost, and quantitative method to investigate the soot volume fraction in flames. However, …
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Interaction of the potential DNA-radiosensitizer 8-bromoadenine with free and plasmonically generated electrons
… like LEEs. Beyond that LEEs can be generated by laser illuminated nanoparticles that are applied in photothermal therapy (PTT) of cancer, which is an attempt to treat cancer by an increase of temperature in the cells. However, the application of halogenated nucleobases in PTT has not been taken …
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Synchronization in Coupled Opto-thermal Silicon MEMS Limit Cycle Oscillators
… coupled, and opto-thermally driven by a continuous-wave helium-neon laser. Experimentally, we demonstrate synchronization in pairs of coupled oscillators which result in reduced frequency fluctuations in the devices. Irregular oscillations are observed at higher input laser powers and are …
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Laser manufacturing of multi-functional and antibacterial surfaces for orthopaedic applications
… of reoccurring infections after the first one1. Laser surface treatment of commercially pure titanium (cp Ti or medical grade 2), which is a commonly used material in medical devices has been shown to improve response to bacteria attempting to attach to the surface2. The aim of this work was to …
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Laser Crystallization of Silicon Thin Films for Three-Dimensional Integrated Circuits
… with Moore's Law. In this thesis, we utilize laser-based and other melt-mediated crystallization techniques to create Si thin films that may be of sufficient microstructural quality for use in monolithic thin-film-based three-dimensional integrated circuits (3D-ICs). Beam-induced …