【作者】 何伟强；

【导师】 顾春明； 沈文忠；

【作者基本信息】 上海交通大学 ， 凝聚态物理， 2007， 硕士

【摘要】 半导体材料的非线性光学特性在光电子器件领域,如全光开关、光学限幅器、光波耦合器等方面有很好的应用价值。非线性光学材料已持续多年是光学、新功能材料领域的热点课题。因此对半导体材料的非线性光学性质的研究有着实际的意义。Z扫描技术作为一种高灵敏度、实验装置简单的测量手段,被广泛应用于研究半导体材料的非线性光学特性。本文首先简述了介质中基本三阶非线性光学过程,继而介绍了非线性光学材料的基本测量方法,即Z扫描技术,同时简单介绍了我们所用的实验装置及仪器。然后,用Z扫描技术分别讨论了半导体碲化锌(ZnTe)晶体及氮化铟(InN)薄膜的非线性光学特性。利用透射Z扫描实验系统,研究了ZnTe晶体在飞秒激光脉冲作用下的非线性光学性质。通过对(110)、(111)及(100)ZnTe晶体的非线性折射率的测量,发现不同晶体取向的晶体中非线性折射率差别很大,推测该差异主要源于晶体中二阶级联非线性效应的贡献,即晶体中THz辐射与线性电光效应共同作用产生的克尔型非线性(Kerr-like nonlinearity)效应。此外,根据晶体中THz辐射对入射激光偏振方向的依赖性,运用理论模型描述了三块晶体中非线性折射率随入射光偏振角的变化关系,从而进一步证明该克尔型非线性效应的更多还原

【Abstract】 The nonlinear optical properties of semiconductors were intensively used in the opto-electronic devices, such as all-optical switches, optical limiters and waveguide formation etc. The investigation of nonlinear optical materials is a hot topic in theoretical and experimental research at all times. Therefore the study of nonlinear optical characteristic of semiconductor is of very important and has practical significance.As a sensitive and simple technique, Z-scan is widely applied in the investigation of the nonlinear optical media. Firstly, we review the basic third-order nonlinear optical processes in media. Then we also introduce the principles of Z-scan technique, together with the brief description of the instruments and apparatus. The main part of this thesis on the study of optical nonlinearities in ZnTe and InN semiconductors using Z-scan technique with femtosecond laser pulses.By performing the single-beam Z-scan with femtosecond laser pulses on (110), (111) and (100) oriented ZnTe crystals, we present the experimental evidence of a new kind of Kerr-like nonlinearity induced via terahertz (THz) generation and the linear EO effect in the media. In addition, we have proposed a model, taking into account the Kerr-like更多还原