周期极化非线性晶体中太赫兹波辐射研究

从理论上详细研究了飞秒激光在周期极化非线性晶体中由光整流效应产生的太赫兹（THz）波辐射。利用天线辐射原理和光栅衍射理论，着重研究THz波辐射的频域场和时域场的分布。讨论和分析了THz波辐射的中心频率、频谱宽度和电场随辐射角的变化。研究表明，THz波的带宽反比于晶体的长度或光栅数，电场随辐射角呈准谐波变化。

THz wave radiation in periodically poled nonlinear crystal

THz wave radiation induced by femtosecond pulse in periodically poled nonlinear crystal is theoretically studied based on optical rectification. Using the principle of the antenna radiation and the theory of the grating diffraction, the study focuses on the distribution of the field of the frequency domain and the field of the time domain. The center frequency, the width of the spectrum and the electronic field of the THz wave are discussed and analyzed varying with the radiation angle. The result of the study shows that the bandwidth of the THz wave is inversly proportional to the length of the crystal and the number of the grating, and that the electronic field varying with the radiation angle is quasi-harmonic.