Transient stimulated brillouin scattering reflectivity in CS2 and SF6 under multipulse employment

Abstract

The multipulse effects on transient stimulated Brillouin scattering (SBS) in CS2 and 20-atm SF6 were investigated using an iodine laser as the pumping source. A simple pulse-dividing scheme was used to obtain a multipulse. The enhancement of SBS reflectivity by multipulse employment was more significant in SF6 because of a longer phonon lifetime requiring more pumping pulses than in CS2. In practice, when the power ratio of two pumps was 1:1.6 and the pump separation was 8 ns, for CS2 the SBS peak-power reflectivity increased twofold in comparison with that of an original single pump, and the absolute reflected power increased simultaneously by approximately 50%. A computer simulation of the double-pulse pumped SBS process was pei formed to examine the detailed interaction between optical waves and acoustic waves in the medium. With the enhancement of acoustic-wave intensity by double-pulse pumping and the dependence on phonon lifetime we can provide a good explanation of our experimental results. (C) 1997 Optical Society of America.