采用真空镀膜技术在石英基板上制备了纯As2S8 以及掺杂As2S8平面波导，通过棱镜耦合技术观察了光阻断效应。结合S和As的外层电子构型，分析了样品内部的化学键结构，利用电子能带结构理论和杂化轨道理论，建立了光阻断效应的动力学方程，并对切断过程进行了数值分析，分析结果与实验数据十分符合，得出该模型能很好地解释光阻断效应的实验现象，并揭示了光阻断效应切断过程的内在机理。

The cut-off process of optical stopping effect in thin film waveguide with doping As2S8 and pure As2S8 is studied. Based on this, the chemical bond structures of the samples are analyzed. With the help of the theory of hybridize valence orbital and the theory of electron energy band gap, the dynamical equation of optical stopping effect is proposed. The numerical analysis results are well agreable with the experimental data, and the cut-off process of optical stopping effect can be explained by the deduction of this model. It reveals the mechanism of cut-off process of optical stopping effect.