克尔介质中脉冲宽度对瞬态热光非线性效应的影响

在纳秒时域，研究了激光脉冲宽度变化对克尔介质中瞬态热光非 线性效应的影响.通过不同脉冲宽度τp下得到的二硫化碳 苯胺黑溶液的Z_scan实验结果，对瞬态热光非线性效应和光克尔效应的共存过程进行了分析 .随着脉冲宽度的增加，观察到了热光非线性效应从瞬态到稳态变化过程和Z_scan峰谷特性 的转变.同时，从声波的传播方程和光波的非线性传播方程出发，用数值计算方法模拟了这 一非线性过程，结果表明数值模拟结果和实验结果是相符的. 关键词： 瞬态热光非线性效应 脉冲宽度 Z_scan 克尔效应

The influence of pulse width on transient thermally induced optical nonlinearities in a Kerr nonlinear medium

We report the experimental results on the effect of pulse width on transient thermally induced optical nonlinearities in the nanosecond regime. We have obtained the Z_scan curves of the CS_(2) solutions of nigrosine for different pulse widths, and analyzed the co_existence of third_order and transient thermally induced optical nonlinearities. The process of changing from transient state to steady_state thermal_induced optical nonlinearities was observed. Meanwhile, we have obtained the results of numerical simulation by solving simultaneously acoustic and electromagnetic wave equations, which agree well with the experimental results.