Remote Sensing and Directed Energy Application of Femtosecond Terawatt Lasers

The ability to propagate high-intensity broadband femtoscond laser pulses to long distances (> 10 km) in the atmosphere constitutes a new frontier in laser physics and nonlinear optics. Supercontinuum (white-light) continuum generation in the atmosphereusing terawatt femtosecond laser pulses have already been suggested for novel LIDAR applications in the spectral range from the UV to IR, to perform range resolved multitrace analysis simultaneously. In addition, the generation of a high-intensity (>1013W/cm2) light channel over long distances offers the possibility to probe nonlinear effects such as Raman processes, harmonic generation, nonlinear frequency mixing, and plasma generation at a remote location. The program will demonstrate applicability tosensor countermeasures and remote sensing by detailed experimentation, using a femtosecond laser system. Long-range propagation experiments using a 500-meter laser range will analyze the effects of initial pulse energy, beam radius, frequency chirp, andwavefront divergence on the propagation distance. Laser pulse propagation dynamics under multiple filamentation conditions will be characterized. Additional experiments will quantify EMP generation from the induced plasma column and laser pulse materialinteractions including surface damage assessment /secondary radiations effects. Simulations will include the usual plasma generation, dispersion and nonlinear effects, as well as vector waves and harmonic generation. This effort will result in a modelthat, when verified by experimentation, will serve as the basis for development of novel, long range LIDAR systems. These systems will be used to detect chemical/biological agents at long ranges, as well as provide a means for remote detection ofatmospheric chemicals and aerosols for monitoring of pollution. These advanced LIDAR systems may also be used to remotely measure atmospheric turbulence, providing improved, early alert of wind-shear to landing aircraft.