In the terahertz (THz) generation driven by two-color laser pulses, the THz wave radiated from the BBO crystal as the effect of the optical rectification is always assumed to be less and negligible. In this paper, the contribution of the optical rectification in the THz radiation driven by two-color laser pulses has been determined quantitatively, by the crucial factors including BBO crystal rotation angle, the pump power of laser, and the numerical aperture of lens. The experimental and simulation results show that the above related factors have dramatically affected the intensity ratio of the THz waves from the plasma and BBO crystal. It is helpful for understanding the mechanism of THz generation from air plasma.

中文翻译：

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双色激光诱导等离子体驱动的太赫兹辐射中的光学整流作用。

在由两种颜色的激光脉冲驱动的太赫兹（THz）生成中，始终假设从BBO晶体辐射出的THz波作为光学整流的影响较小且可忽略不计。在本文中，通过BBO晶体旋转角，激光器的泵浦功率和透镜的数值孔径等关键因素，定量确定了光学整流对由两种颜色的激光脉冲驱动的THz辐射的贡献。实验和仿真结果表明，上述相关因素极大地影响了来自等离子体和BBO晶体的THz波的强度比。这有助于理解空气等离子体产生太赫兹的机理。