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Interferometric grating tilting, laser-damage detection, and deformable gratings for large-scale laser systems

Dr. Jie Qiao, LLE, University of Rochester

Thursday, April 11, 2013
3:30 p.m.–4:30 p.m.
Sloan Auditorium

Abstract:
High-intensity large-scale laser systems require 1.5-meter-scale diffraction gratings with high damage threshold and low wavefront distortion for optimal spatial focusing and temporal compression on target. To overcome the available-gratings size limitation, a near-field tiling technique has been developed, implemented, and automated to interferometrically align three half-meter gratings. An optical model has been developed to analyze tiling-parameters sensitivity and focal-spot degradation for a compressor composed of four such assemblies. Two large-aperture tiled-grating compressors have been built and activated. A grating-inspection system based on dark-field imaging and a damage-analysis method have been developed to measure in-situ laser-induced damage on a 1.5-m grating in vacuum.These techniques have enabled OMEGA EP to operate as the only kilojoule picosecond laser users’ facility in the world since 2008 with ~2000 shots delivered. A meter-scale deformable-grating–based pulse compressor with optimized actuator positions was designed to reduce wavefront distortion, the application of which would significantly enhance the potential for pulse recompression and focusability. The system output energy can potentially be scaled up as well. 

Bio:
Dr. Jie Qiao has been a scientist in laser-system and optical technologies at Laboratory for Laser Energetics, University of Rochester since 2005. She has provided scientific and project leadership during the development, activation, and operation of the kilojoule, petawatt OMEGA EP short-pulse laser systems, focusing on large-scale optics alignment and metrology, optical system modeling for laser pulse compression and focusing, laser diagnostics, and laser performance evaluation. Prior to that, she was a senior optical engineer in both startup and corporate settings, focusing on photonics for optical communications, optical metrology and optical instrumentation. She obtained her Ph.D. in Electrical and Computer Engineering, the University of Texas at Austin in 2001, her M.S. in Precision Instruments and Fine Mechanics from Tsinghua University in 1997. She has recently obtained a M.B.A, concentrating in Entrepreneurship, Marketing, Finance, and Competitive & Organizational Strategy, from the Simon Graduate School of Business, University of Rochester.

Dr. Qiao holds two US patents, has authored close to a dozen peer-reviewed journal articles, and has made more than 30 presentations in national and international conferences. She served as the Program Committee Co-Chair for the International Committee on Ultrahigh Intensity Lasers (ICUIL) 2012 conference. Her research interest lies in Metrology for Optics and Imaging Quality Testing, Laser Applications for Advanced Manufacturing, Active Optics and Controls, and Optical Instrumentation.