Coherent detection of terahertz pulses via gas plasma induced by few-cycle laser pulses with fixed carrier envelope phase

Abstract

The time behavior of gas plasma induced by a few-cycle laser pulse with a simultaneously incident terahertz (THz) pulse is investigated via a transient photocurrent model. The results show that the second-harmonic intensity emitted from the gas plasma can well replicate the THz waveform if the laser pulse has a fixed carrier envelope phase. Based on these we propose a approach for THz coherent detection, which could realize coherent THz detection with very low laser energies and without a bias field, and may be very useful in some fields, such as remote THz sensing.