Seed source for plasma compression in the long wavelength infrared

Two color laser pulses are used to form an air plasma and generate broadband infrared radiation suitable as a seed for backward Raman amplification of CO2 pulses. Broadband in the atmospheric window from 8 14 μm is observed. The characterized using long wavelength grating spectrometer specially designed accept ionizing filament at its input plane. yield greatly enhanced by chirping drive pulse, but this affects spectrum well. Unidirectional pulse propagation simulations suggest that due part dependence nonlinear refractive index on duration.