Fundamental Studies of Self-Induced Waveguides in the Atmosphere at Various Wavelengths and Pulse Durations

We propose a fundamental study of filamentation in air that will combine the theoretical expertise at the University of Arizona in simulating these nonlinear phenomena, the experimental facilities at the University of New Mexico in ultrafast diagnostics,and the experience at Lite Cycles, Inc. in the design and construction of high-power, short-pulse lasers. In Phase I of this program, we will make measurements of air parameters at various wavelengths to refine the simulation. We will perform directspatio-temporal measurements on IR and UV filaments by letting them diffract in a vacuum chamber sealed by an aerodynamic (supersonic) window. This technique will enable us to make measurements on pulse parameters inside the filament, which are notaffected by nonlinear effects usually occuring at a solid reflecting interface. We expect that the combination of measurements and simulation will enable us to get a complete understanding of the self-trapping mechanism in air, and thus select the bestwavelength to be used in Phase II of the program.This project will have applications in creating a remote bright point source for lidar applications as well as for wavefront correction.