采用瞬态受激旋转拉曼散射(SRRS)模型,详细考虑了激光脉冲波形、介质的非线性极化、泵浦光的衰减、斯托克斯光的非线性放大以及拉曼线宽等诸多因素,对强紫外激光束在空气中长程传输过程产生的SRRS效应进行了研究.讨论了产生SRRS效应的阈值条件,详细分析了SRRS效应对激光光束质量的影响.

In the inertial confinement fusion (ICF), to achieve optimum fuel compression, the laser beams must irradiate the target uniformly, which require excellent beam quality. The effect of stimulated rotational Raman scattering (SRRS) leads to losses of beam quality. In this paper, using the modeling of transient stimulated rotational Raman scattering and considering many factors including the pulsed-shape of laser beams, the nonlinear polarization of the medium, the depletion of pump laser, the nonlinear amplifier of the Stokes field, and the Raman bandwidth, etc. the SRRS of high-power ultraviolet laser beams in long air path was studied. The conversion efficiency of SRRS and the threshold condition for the SRRS effect was also discussed. The effect of SRRS on laser beam quality was analyzed in detail.