Brillouin scattering, two-plasmon decay, and self-focusing in underdense ultraviolet laser-produced plasmas

Abstract

Underdense foam targets were irradiated with a single UV laser beam at intensities up to 1015 W/cm2. The incident laser propagated into the foam a distance of 500–1000 μm, depending on the average target density. The backscattered Brillouin and 3ω0/2 radiation were observed to have the same dependence on the incident laser intensity, indicating a strong interrelation of these processes. A possible coupling mechanism is proposed.