讲座题目：Ultrafast nonlinear optics at ionizing intensities

主讲人：Associate  Professor Pavel Polynkin

主持人：康斯坦丁研究员

报告时间：2019.3.19.上午10：00

报告地点：理科大楼A814室

报告摘要：

Extreme nonlinear optics is an interdisciplinary branch of laser science that deals with optical intensities exceeding damage threshold for most materials. The major focus is on the studies of plasmas produced by strong-field ionization and on the utilization of these plasmas for various applications ranging from laser ablation to weather control. Past investigations in this broad field used ultrashort-pulse laser systems operating in the near-infrared, at around 1 μm wavelength. Pulse repetition rates were usually limited to 1 kHz. In this talk, I will discuss basic and applied aspects associated with the extension of these studies to the mid-infrared and long-wave infrared regimes and to very high pulse repetition rates. I will further discuss two specific applications: air lasing and channeling the electrical breakdown of air. In the air lasing concept, a powerful laser beam propagating into the atmosphere, remotely pumps population inversion in the constituents of air. The goal is to produce an impulsive, backward propagating, laser-like radiation from a remote location in the sky. This research is important because air lasing enables single-ended schemes for remote sensing in the atmosphere. Both the excitation laser source and the detector are co-located at the same position either on the ground or on a flying airplane. No physical probe laser, pointing towards the observer from behind the remote area of interest, is required. The second application of air plasma that I will discuss is for channeling the electrical breakdown of air. This problem has been extensively investigated for several decades, motivated by the search for a flexible solution for channeling lightning. Previously investigated schemes were based on the application of a single, energetic, nanosecond or femtosecond laser pulse, to produce a guiding channel in the air. In the single-pulse scheme, basic physics limits the maximum extent of the discharge guidance by few meters. I will discuss new approaches to overcoming this range limitation.

报告人简介：

Education:

•Ph.D. in Electrical Engineering, Texas A&M University, College Station, TX (2000)

•M.S. in Applied Physics and Mathematics, Moscow Institute of Physics and Technology (1995)

•B.S. in General and Applied Physics, Moscow Institute of Physics and Technology (1993)

Employment history:

2007 – Present: Associate Research Professor, College of Optical Sciences, University of Arizona, Tucson, AZ

2004 – 2007: Assistant Research Professor, College of Optical Sciences, University of Arizona, Tucson, AZ

2003 – 2004: Research Associate, Optical Sciences Center, University of Arizona, Tucson, AZ

2000 – 2003: Optical Engineer, Capella Photonics, San Jose, California

Professional activities:

•Member of the Ultrafast Optics, Optoelectronics and Applications Committee, Conference on Lasers and Electrooptics (CLEO) (2013 – 2015)

•Member of the organizing committee, Conference on High-Intensity Lasers and High-Field Phenomena (HILAS) (2016)

•Co-organizer of the Special Symposium on Remote Atmospheric Lasing at CLEO 2015

•Guest editor of the special joint issues of JOSA B and Applied Optics on laser interaction with materials (2014, 2018)

•Visiting scientist at the Lawrence Livermore National Laboratory (2013 – 2015)

•Guest Professor at the Abbe Center of Photonics, Friedrich-Schiller University Jena (2013)