抽运能量对受激布里渊散射光限幅特性的影响

Optical Limiting Characteristics Dependent on Pump Energy in Stimulated Brillouin Scattering Process

采用布里渊噪声起源模型 ,数值模拟了受激布里渊散射介质CCl4对波长 10 6 4nm的Nd∶YAG纳秒激光脉冲的传输特性及光限幅特性。入射抽运脉冲能量较低时 ,非线性介质对纳秒激光脉冲呈光学透明。入射抽运脉冲能量高于受激布里渊散射产生阈值后 ,透射脉冲峰值受限 ,脉宽压缩 ,能量趋于饱和 ,说明该光学系统同时具有光功率限幅和能量限幅的光限幅特性。利用理论模型模拟了如下光限幅参量 :透射脉冲峰值功率、透射能量、能量透射率、脉宽压缩率依赖抽运光能量的变化关系。相应的理论模拟计算结果由实验进行验证 ,实验结果与理论模拟相符合。

Adopting a noise-initiation mode of stimulated brillouin scattering (SBS), optical limiting effect are numerically simulated by using 7 ns, 1064 nm, Nd∶YAG laser pulses within CCl 4 liquid in SBS process. When the pump energies are low, the nonlinear medium can be optical transparent. When pump energies are higher than the threshold of stimulated Brillouin scattering, the peak powers of nanosecond laser pulses are limited, pulses are narrowed and the energies tend to saturated. This means the optical limiting has both power limiting and energy limiting characteristics. The relationships of optical limiting effect such as output peak power, output energy, transmissivity and pulse compression ratio versus pump energy are investigated by a theoretical model. The experimental results of above optical limiting effects were given. In authors' experimental regime, results were in good agreement with the conclusions predicted by theoretical simulations.