Measurement of Quadratic Terahertz Optical Nonlinearities Using Second-Harmonic Lock-in Detection
Measurement of Quadratic Terahertz Optical Nonlinearities Using Second-Harmonic Lock-in Detection
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DOI：
10.1103/physrevapplied.10.044007
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发表时间：
2018-10-02
影响因子：
4.6
通讯作者：
Talbayev, Diyar
中科院分区：
文献类型：
--
作者：
Lin, Shuai;Yu, Shukai;Talbayev, Diyar
提出了一种测量太赫兹时域光谱中二次太赫兹光学非线性的方法。我们使用旋转线偏振器（偏振斩波器）来调制入射太赫兹脉冲序列的幅度。我们使用相敏锁定检测在调制频率的基波和二次谐波分离的材料的响应，是线性的和二次的太赫兹电场。我们通过测量GaP晶体中存在更强的线性电光效应时的二次太赫兹克尔效应来证明这种方法。该方法可用于非中心对称介质中太赫兹二次谐波的时域光谱检测，在非线性太赫兹光子学及相关技术中具有广阔的应用前景.
We present a method to measure quadratic terahertz optical nonlinearities in terahertz time-domain spectroscopy. We use a rotating linear polarizer (a polarizing chopper) to modulate the amplitude of the incident terahertz pulse train. We use phase-sensitive lock-in detection at the fundamental and the second harmonic of the modulation frequency to separate the materials' responses that are linear and quadratic in a terahertz electric field. We demonstrate this method by measuring the quadratic terahertz Kerr effect in the presence of the much stronger linear electro-optic effect in the (110) GaP crystal. We propose that the method can be used to detect terahertz second-harmonic generation in noncentrosymmetric media in time-domain spectroscopy, with broad potential applications in nonlinear terahertz photonics and related technology.