啁啾脉冲光谱仪法探测THz辐射的时间分辨率极限

介绍了啁啾脉冲光谱仪法探测THz(1012Hz)辐射的基本原理,该方法克服了时间延迟扫描方法测量速度的缺陷,可以实现实时测量。被THz电场调制的啁啾探测光脉冲通过光谱仪后,待测THz电场时域波形被光谱仪在空域上展开,因此一次测量即可得到一个THz电场的时域波形。但是光谱仪的引入实际上相当于进行了一次傅里叶变换,使得最终得到的测量结果不是THz电场本身,而是与另外一个函数的卷积,因此从理论上证明了啁啾脉冲光谱仪法探测THz辐射存在时间分辨率极限。将理论结果与已有的实验结果进行对比,得到了很好的一致性。

The limitation of time resolution of the chirped pulse spectral encoding technique

The principle of chirped pulse spectral encoding technique is described.It has an advantage of the measurement speed,which is just the disadvantage of the scanning delay line.Real-time measurement can be realized by the technique.After passing through a spectrometer,the measured THz waveform is decoded in spatial.Therefore it is a single-shot measurement.However,the use of spectrometer is actually performed a Fourier transformation,the measured result is not THz electric field itself but the convolution of the THz and another function. It verifies that the technique has time resolution limitation.Comparing the theoretical results with the experimental results,a perfect consistency is arrived.