Title: Ultrafast nonlinear optics at ionizing intensities

Abstract: Extreme nonlinear optics is an interdisciplinary branch of laser science that deals with optical intensities exceeding the ionization threshold for most materials, usually accessible through the use of energetic, ultrashort laser pulses. I will discuss several research projects related to laser-induced ionization that I have been involved in, over the last decade. One of our major research directions is the studies of the nonlinear self-channeling of ultrashort-pulse laser beams in the atmosphere (filamentation) and the associated phenomena. We have applied spatial and temporal shaping of the laser beam to control its highly nonlinear propagation and developed techniques for the enhancement of the laser-generated plasmas by using long-pulse heater laser beams and high-power microwaves. Potential applications of these studies are in directed energy and remote sensing. Another major research direction that I will talk about is on the sub-surface modifications of transparent materials by ultrashort-pulse laser beams tightly focused under the surface of the sample. Rapid deposition of the optical energy in the microscopic interaction volume drives a confined microexplosion and results in the generation of exotic, super-dense material phases. Finally, I will discuss the motivation for extending the intense laser-matter interaction studies from the extensively explored near-infrared regime to longer-wavelength driver sources and our on-going program on the construction of a terawatt-class, ultrashort-pulse laser system operating in the long-wave infrared.

About the Speaker: Pavel Polynkin received his MS degree in Applied Physics and Mathematics from Moscow Institute of Physics and Technology in 1995 and his PhD degree in Electrical Engineering from Texas A&M University in 2000. His graduate research was on quantum coherence effects in atoms and molecules and on optical fiber sensors for precision measurements of rotation rates and electromagnetic fields. Since 2003, he has been with the College of Optical Sciences at the University of Arizona, where he is currently a Research Professor. Dr. Polynkin’s current research interests are in ultrafast laser-matter interactions, strong-field ionization, remote optical sensing, and long-range nonlinear propagation of ultrashort-pulse laser beams, as well as in the development of ultrashort-pulse laser sources based on fiber and solid-state gain media.