The influence of a short intense (with an electric field strength up to 250 kV cm -1 ) terahertz (THz) pulse on the generation of second harmonic (SH) of Ti : sapphire laser radiation in crystals of zinc blende type (InAs and GaAs), characterised by nonzero bulk quadratic susceptibility, is investigated. It is experimentally shown for InAs(100) that, in the case of s-polarised first and second harmonics, an application of s-polarised THz field changes significantly the SH signal. The THz field-induced azimuthal dependence of the SH signal is in good agreement with the results of theoretical calculation within a phenomenological approach. The dependence of the SH signal on the delay time between the optical and THz pulses is investigated. This dependence for the GaAs crystal repeats the envelope of the THz pulse intensity, whereas in the case of InAs crystal there is a significant discrepancy, caused by the nonlinear dynamics of strong THz field in InAs.

中文翻译：

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飞秒光学和强太赫兹场的共同作用下锌共混物晶体的二次谐波产生

短时强（电场强度高达250 kV cm -1）太赫兹（THz）脉冲对锌混合型晶体（InAs和GaAs）中的Ti：蓝宝石激光辐射的二次谐波（SH）的产生的影响），以非零体积二次磁化率为特征进行了研究。对于InAs（100），实验表明，在s极化的一次谐波和二次谐波的情况下，使用s极化的THz场会显着改变SH信号。太赫兹场诱导的SH信号的方位角依赖性与现象学方法中的理论计算结果非常吻合。研究了SH信号对光脉冲和THz脉冲之间的延迟时间的依赖性。对GaAs晶体的这种依赖性重复了THz脉冲强度的包络，