真空度对强紫外激光在空气中长程传输的影响

 采用瞬态受激旋转拉曼散射(SRRS)模型，并充分考虑非线性介质分子密度、增益系数、泵浦光的衰减、斯托克斯光的非线性放大以及初始的随机斯托克斯散射场等因素，研究了空气真空度对强紫外激光在空气长程传输过程中产生的SRRS效应的影响。结果表明，真空度对SRRS效应的阈值传输距离和Stokes光的转换效率的影响较大，随着真空度的提高，Stokes光的转换效率将降低，产生SRRS效应的阈值传输距离将增大。因此，在实际工作中，可以采用真空度较高的激光传输环境来抑制SRRS效应的产生，以减小入射泵浦光能量的衰减并提高光束质量。

Effect of vacuum degree on high power ultraviolet laser beams in long air path

Using the model of transient stimulated rotational Raman scattering(SRRS) and considering many factors,such as the molecular density of nonlinear medium,the gain coefficient,the depletion of pump laser,the nonlinear amplification of the Stokes field,and the initial random Stokes scattered field,etc,the effect of vacuum degree on the SRRS of high-power ultraviolet laser beams in long air path has been studied.The Stokes conversion efficiency decreases and the propagation distance of the threshold increases with the increase of vacuum degree.In practice,in order to decrease the effect of SRRS on the energy and beam quality of high power ultraviolet laser beam,the atmospheric envionment of laser propogation with high vacuum degree can be used to suppress the SRRS effect.