Plasma enhanced frequency conversion of ultra broad bandwidth laser pulses to optical harmonics focused in atomic and molecular gases

Colorado State University, Fort Collins CO

Investigators

Abstract

This project explores ultra-broad bandwidth generation of optical pulses in the ultraviolet (UV), deep UV, and vacuum UV (VUV) spectral ranges. Conversion of few cycle pulses to the UV has traditionally been limited by dispersion and transparency constraints from dispersive crystals and by inherent low conversion efficiency in low density gases. This work will develop a detailed understanding of the physics of few-cycle light pulses propagating in spatially structured plasmas for optimization of efficient conversion to short wavelength odd-order optical harmonics. Besides investigating new optical physics, these studies will pave the way for the generation of ultra-broad bandwidth pulses compressed to <5-fs in duration in the UV, deep UV, and VUV spectral regions. Efficient sources of VUV few cycle laser pulses will prove to be an invaluable tool for probing excited state dynamics of molecules and for probing electronic structure of molecules and materials. The ultrafast laser pulses will serve as excellent probes of fast processes such as dynamics at conical intersections, photoisomerization, photodissociation, and photobiology, to name a few. An area where application of these tools is particularly apt is for studying photoconversion processes such as dynamics in light harvesting complexes and electron transfer dynamics and dye sensitized photoconversion cells. Undergraduate researchers will be included in all aspects of this project, focusing on research areas of short pulse propagation, nonlinear optics, ultrafast optics, plasma physics, and molecular spectroscopy. Involvement by students through summer undergraduate programs (REU, McNair, LSAMP) will encourage students from diverse backgrounds. In addition, the PI will continue revising and delivering his "optics show" for K-2nd graders.