Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 3 of 3

Full-Text Articles in Physics

Q-Switched And Mode Locked Short Pulses From A Diode Pumped, Yb-Doped Fiber Laser, Seth M. Swift Mar 2009

Q-Switched And Mode Locked Short Pulses From A Diode Pumped, Yb-Doped Fiber Laser, Seth M. Swift

Theses and Dissertations

A diode-pumped, ytterbium (Yb)-doped fiber laser system was designed and demonstrated to operate in continuous wave (cw), passively Q-switched and possibly passively mode locked operation. To our knowledge, this was the first fiber laser oscillator built at the Air Force Institute of Technology. A Cr4+:YAG (Chromium: Ytterbium Aluminum Garnett) crystal was used as a saturable absorber to generate Q-switched pulses. Attempts to mode lock the laser were performed using a semiconductor saturable absorber mirror (SESAM) and through nonlinear polarization rotation (NPR). The best output power result was 5 Watts (W) while pumping at 8.3 W, yielding 60% efficiency …


Nanocomposite Thin Films Of Au Nanoparticles Embedded In Yttria-Stabilized Zirconia For Plasmonic-Based Harsh Environment Gas Detection, Phillip Henry Rogers Jan 2009

Nanocomposite Thin Films Of Au Nanoparticles Embedded In Yttria-Stabilized Zirconia For Plasmonic-Based Harsh Environment Gas Detection, Phillip Henry Rogers

Legacy Theses & Dissertations (2009 - 2024)

Increased health concerns due to the emission of gases linked to the production of tropospheric ozone by petroleum based fuel burning engines has resulted in the codification of more stringent emissions regulations domestically. Emissions regulations on commercial jetliners are one of the areas to be met with stricter standards. Currently there is not a sensing technology that can detect the emissions gases in the exhaust stream of a jet turbine engine with lower detection limits that meet these standards.


Pressure Induced Phase Transformation Of Sno2: An Ab Initio Constant Pressure Study, Daniel Tesfai Yehdego Jan 2009

Pressure Induced Phase Transformation Of Sno2: An Ab Initio Constant Pressure Study, Daniel Tesfai Yehdego

Open Access Theses & Dissertations

The behavior of SnO2 under rapid hydrostatic pressures is studied using constant-pressure ab initio simulations. The rutile-type SnO2 gradually transforms into the CaCl2-type structure at 15 GPa. At a pressure of about 20 GPa, a phase transformation into a cubic fluorite-type structure is observed. The orthorhombic Pnma cotunnite-structured phase is observed above 150 GPa. The mechanisms of these phase transformations at the atomistic level are discussed.