Numerical analysis and experimental investigation of beam quality of SBS compressor with multipass Nd:YAG amplifier

摘要

Abstract: The results of the numerical simulation of the laser beam quality changes after propagation through the passive and active optical systems with the linear and nonlinear aberrations are presented. The new algorithm for the calculation of the phase conjugation by steady-state SBS is developed. It is found that the parameter M$+2$/ of the Stokes beam in the saturation regime is often nearly the same as that of the pump beam. The generation of short (approximately 1.5 nsec) pulses with energies exceeding 4 mJ has been obtained using passive Q-switching of the short (approximately 10 cm) resonator of Nd:YAG laser by GSGG:Cr,Nd crystals. After SBS-compression the pulses with approximately 120 psec duration and with energies of approximately 1 mJ have been obtained. Four-pass Nd:YAG amplifier amplifies the pulses to the energies approximately 500 mJ with the duration of pulses of approximately 170 psec. Experimentally obtained results are in good agreement with the mathematical modelling of short pulse generation and amplification.!25