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.
Results
Showing 1 to 20 of 107 for “"Laser Power"”.
-
Approximate solution of melt depth inside titanium during laser materials processing
The use of lasers has increased in areas of science, engineering and medicine. Their advantages over the traditional methods of thermal application are their ability to localize thermal treatments, ability to deliver high power density and to complete thermal processes in extremely short time …
-
Microwave Beam Diagnostic of Laser-Induced Plasmas
… the use of micro-impulse radar to detect laser-induced plasmas. The MIR actively interrogates the plasma to produce a reflected microwave signal from the plasma, and the device also detects the acoustic signature of the plasma. The acoustic MIR signal is similar to the signal received by a …
-
A pulsed laser loading technique for controlled dynamic loading of nanostructred materials
This thesis presents an improved laser loading technique for controlling and calibrating the stress waves created from this ultra-high loading rate technique. In the high-power pulsed laser loading technique, a laser produced compressive stress pulse passes through a substrate and reflects at a …
-
3-D Printing, Characterizing and Evaluating the Mechanical Properties of 316L Stainless Steel Materials with Gradient Microstructure
… parameters (hatch spacing, scanning speed, and laser power and scanning speed) of the Selective Laser Melting (SLM). The Materials with Graded Microstructure (MGMs) are characterized by optical and scanning electron microscopy (SEM). Image processing framework is utilized to reveal the …
-
Active wavefront correction in laser interferometric gravitational wave detectors
As the first generation of laser interferometric gravitational wave detectors near operation, research and development has begun on increasing the instrument's sensitivity while utilizing existing infrastructure. In the Laser Interferometer Gravitational Wave Observatory (LIGO), significant …
-
Investigation of Ultracold Rubidium Atoms in a Pulsed Far off Resonance Trap
… of a pulsed optical dipole force trap which uses laser light to confine ultracold rubidium (Rb) atoms. Because the laser frequency is detuned far from the atomic resonance frequency, the optical dipole force trap is also called a "far-off-resonance trap" (FORT). The use of pulsed laser light to …
-
Multi-Physics Sensing and Real-time Quality Control in Metal Additive Manufacturing
Laser powder bed fusion is one of the most effective ways to achieve metal additive manufacturing. However, this method still suffers from deformation, delamination, dimensional error, and porosities. One of the most significant issues is poor printing accuracy, especially for small features such …
-
Extreme optomechanically induced transparency
… ultra low loss mechanical oscillators and high laser power to achieve extremely strong optical induced transparency effects. This system modifies the light transmission properties of the optical cavity reducing the transmission by a factor of 3 x 10 -3 at the highest power levels. A linewidth …
-
Direct Metal Laser Sintering of Titanium implant with Tailored structure and Mechanical Properties
Direct Metal Laser Sintering has attracted much attention over the last decade for producing complex parts additively based on digital models. The capability and reliability of this process has stimulated new design concepts and has widened the manufacturing perspective of product customisation. …
-
Modal analysis of laser vibrated structures
This thesis describes the laser irradiation of metallic structures to excite mechanical vibrations within those structures. As found by other authors, single high-power laser pulses ablate the irradiated surface material and may impulsively excite structural vibration; however, the use of laser …
-
Wavefront modelling and sensing for advanced gravitational wave detectors
The Advanced Laser Interferometer Gravitational-wave Observatory (aLIGO) directly detected gravitational waves for the first time on the 14th of September 2015. In 2017 the detection of gravitational waves from a binary neutron star merger was subsequently followed up by observations by optical and …
-
Applications of infrared fibers in temperature sensing
… the transmission of <i>CO</i> and <i>CO</i>₂ laser power, and in several sensing mechanisms. This thesis presents an overview of these new fibers and how they can be applied in noncontact temperature measurement. Fiber optic temperature sensing is thus reviewed, and an optical fiber pyrometer …
-
Reactive flow visualization through high-speed optical laser diagnostics
… was demonstrated using temporally-resolved laser diagnostics to visualize: 1) The turbulent flow field with particle image velocimetry (PIV); and 2) the distribution of combustion radicals, by planar laser-induced fluorescence (PLIF). This allows for the visualization of the flame surface …
-
An investigation of the temperature distribution induced during laser chemical vapor deposition (LCVD) of titanium nitride on titanium-aluminum-vanadium
… and spatial profile of deposits formed using laser chemical vapor deposition (LCVD), spatially resolved multi-wavelength pyrometry measurements of the substrate temperature have been made during LCVD of titanium nitride (TiN) on Ti-6Al-4V substrates. The precursors that have been used are …
-
A high average-current electron source for the Jefferson Laboratory free electron laser
The spectral output power from the Jefferson Laboratory infra-red free electron laser is primarily limited by the performance of the electron injector. Free electron laser power is directly proportional to the electron beam current and at present the electron injector is limited to 10mA average …
-
Development and spatio-spectral mapping of a capillary high harmonic source
… contributions made to the field are: A novel laser mode quality measuring device. (Laser mode quality strongly affects the efficiency of the capillary launch). A study of the spectral output of the system as a function of gas pressure, laser power, and laser spectral phase. An analysis …
-
Spontaneous chiral ordering in titanium diselenide
… Four samples' photocurrent response to a 120 meV laser was subsequently measured as a function of temperature and laser power. The onset of the CPGE at approximately 174 K confirms the emergence of chiral order below the regular CDW transition at 197 K. Furthermore, we were able to train the …
-
Laser induced fractures in porous media.
… technique using a clean energy source (laser) has been proposed and discussed in this research. In order to evaluate the feasibility of using laser-induced fractures as an alternative technique, an analytical model has been developed to calculate temperature distribution during the laser …
-
Pulsed-Laser Ultrasound Generation in Fiber-Reinforced Composite Material
A laser-based ultrasonic technique using a pulsed laser for stimulating ultrasonic waves in fiber-reinforced composite materials is the subject of investigation. For convenience, the material is chosen to be homogeneous transversely isotropic. The study is strictly limited to the laser power …
-
Scientific principles for the electric oxygen-iodine laser
… understanding of the electric oxygen-iodine laser (EOIL). The research reported on herein was largely conducted between the years of 2006 and 2011. The work comes on the forefront of EOIL development, recently demonstrated in 2005 with positive gain and lasing through a long-term partnership …
Page 1 of 6