Previous research shows that few-cycle laser (FCL) pulses with low energy and without a bias field can be used to coherently detect terahertz (THz) pulses. As we know, it is very difficult to stabilize the carrier envelop phase (CEP) of FCL pulses, i.e. there are some random fluctuations for the CEP. Here we theoretically investigate the influence of such instability on the accuracy of THz detection. Our results show that although there is an optimum CEP for THz detection, the fluctuations of CEP will lead to terrible thorns on the detected THz waveform. In order to solve this problem, we propose an approach via using two few-cycle laser pulses with opposite CEPs, i.e. their CEPs are differed by <i>π</i> .
Wang Kejia, Gu Xinyang, Zhang Zhenwei, Yang Zhengang, Liu Jinsong, Wang Shenglie. A proposed approach for detecting terahertz pulses by using double few-cycle laser pulses with opposite carrier envelop phases[J]. Chinese Optics Letters, 2018, 16(9): .
