中文摘要：

在不同激光脉冲激发下，用Z-扫描法测量了甲苯的三阶光学非线性，发现其非线性折射率随着脉冲宽度增加而增大（从150fs时的3．7×10^-16cm^2／W到4ns时的2．6×10^14cm^2／W）．在波长532nm、光强4．73×10^14w／m^2和21ps的脉冲作用下，甲苯溶液呈现反饱和吸收现象．结果表明，该吸收效应主要来自于导致该分子中苯环结构π-π电子跃迁的双光子吸收的贡献．

英文摘要：

The nonlinear refractive index （γ） of toluene was measured using the Z-scan technique and laser radiation of various pulse durations. The growth of γ with the increase of the pulse duration was observed （ from 3. 7 × 10^-16 cm^2/W at 150 fs to 2. 6 × 10^-14 cm^2/W at 4 ns ） . The simultaneous influence of mechanisms leading to nonlinear refraction and in toluene was analyzed. Two-photon absorption was proved to be the predominant mechanism causing the reverse saturation absorptive behavior.