Angular Distribution and Pulse Compression of Stimulated Raman Scattering in Ba(NO3)2 Crystal
Ba(NO3)2晶体受激拉曼散射的角度分布和脉冲压缩

The high-efficiency SRS in barium nitrate (Ba(NO3)2) crystal was obtained pumped by a Q-switched Nd:YAG laser (532 nm) operated at 30 Hz.In the forward scattered direction, the first (563 nm),second (599 nm) and third (639 nm) Stokes pulses were presented,the radiation fields of which had cone structures with the scattered angles of 1.7°,3.5° and 5.0°,respectively.Furthermore,it was pointed out that the angular distribution of Stokes radiation was independent of the pump intensity in this work.The results show that the angular distributions of SRS in Ba(NO3)2 crystals are mainly attributed to the phase matched process.The pulse widths of the pump, first, second and third Stokes pulses were measured to be 11.6 ns,9.8 ns,8.4 ns and 4.5 ns, respectively.This indicates that SRS in Ba(NO3)2 crystals can provide the possibility of effective pulse compression and increase of peak pulse intensity.With the pump intensity of about 150 W/cm2, the maximum conversion efficiencies of the first,second and third Stokes pulses were 23.5%,8.8% and 3.4%,respectively.Moreover,the saturation phenomenon of SRS efficiency was experimentally observed,which was due to the thermal loading in the Ba(NO3)2 crystal.