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研究了低温生长砷化镓光电导天线(LT-GaAs PCA)产生太赫兹(THz)波的辐射特性。利用太赫兹时域光谱(TDS)技术测量了光电导发射极在飞秒激光作用下辐射的太赫兹脉冲,得到了时域发射光谱,并通过快速傅里叶变换(FFT)得到相应的频域光谱。结果表明,低温砷化镓光电导天线产生的太赫兹波信号比飞秒激光激发半导体表面产生的太赫兹波信号具有更高的强度和信噪比;太赫兹波信号与光电导天线的偏置电压成线性关系;随着抽运激光功率的增强,太赫兹波信号增大并出现饱和。
The radiation characteristics of terahertz (THz) waves generated by low-temperature growth GaAs PCAs were investigated. The terahertz pulse radiated by the photoconductive emitter under the femtosecond laser was measured by using the terahertz time-domain spectroscopy (TDS) technique to obtain the time-domain emission spectrum. The corresponding frequency domain was obtained by the Fast Fourier Transform (FFT) spectrum. The results show that the terahertz wave signal generated by the low-temperature gallium arsenide photoconductive antenna has higher intensity and signal-to-noise ratio than that of the terahertz wave generated by the femtosecond laser-excited semiconductor surface. The terahertz wave signal and the bias of the photoconductive antenna The voltage becomes a linear relationship; as the pump laser power increases, the terahertz signal increases and saturates.