Progress in the development of a high average power ultra-broadband infrared radiation source

This paper describes numerical and analytical studies on the optimization o f the ultra-broadband infrared (IR) source, a novel high average-power devi ce [1]. The main objective of current studies was the reduction of weight, size, and cost of the system by devising a scheme to generate the two close ly spaced radiation lines with a single laser driver instead of the two CO2 transversely excited atmospheric pressure (TEA) lasers envisioned in the i nitial work. By inducing the modulation instability in nonlinear media, we have obtained as good or better results as in our previous studies but with one of the TEA lasers replaced by a very low-power driver that provides th e seed radiation for the excitation of the instability. Even more important ly, we have demonstrated that the second high peak-power TEA laser can be r eplaced by a compact, light weight, low peak-power driver by focusing the r adiation to a tighter spot. The average power of the source is maintained a t the previous level by operating at higher duty factor, In the new low-pea k-power operating regime, the output spectrum is very similar to that of th e high-power regime, provided that the ratio of the peak power to the nonli near length that scales proportionally to the area of the laser spot remain s fixed.