基于SBS效应激光波长对光学材料损伤的影响

从耦合波理论出发,采用纵向受激布里渊散射(SBS)模型,通过时域有限差分法数值求解了瞬态SBS耦合波方程组,得到了泵浦光、Stokes光强度及声波产生应力随时间的分布;研究了在三种常见波长激光(基频、倍频和三倍频)作用下SBS效应的发展过程及其对光学材料损伤过程的影响。结果表明:种子光作用主要体现在SBS起振阶段,一旦进入稳态阶段,Stokes光强及应力发展的最大值、稳态值依赖于泵浦光的大小;在相同脉冲宽度下,激光波长越短,SBS发生越早,发展越快,更易造成光学元件的力学损伤;三倍频激光产生最大应力为基频光产生最大应力的100倍,且相比于倍频激光,产生最大应力的时刻要提前15ns。

Effect of wavelength on damage of optical materials with SBS

The transient stimulated Brillouin scattering (SBS) process was studied based on the coupled-wave theory. The time-varying distributions of the intensities of pump light, Stokes light and induced stress were obtained by solving the nonlinear coupled-wave equations with the finite difference method. The effect of wavelength, as well as the intensities of pump light and Stokes light, on SBS process are investigated, the results shows the Stokes light takes effect in initial stage mainly, while the pump light works in steady stage; And the stress induced by SBS process varies largely with different wavelength. In addition, the shorter wavelength is, the faster stress develops, which results in damage to materials easier; The induced stress by 3 laser is 100 times as large as the lasers. The moment that SBS occurs for 3 laser is 15ns earlier than that for 2 laser.