THz generation by cosh-Gaussian lasers in a rippled density plasma

摘要

This paper presents a scheme to achieve THz radiation by the beating of cosh- Gaussian lasers in spatially periodic density plasma (ripple density). Here, the lasers exert a nonlinear ponderomotive force along the transverse direction which imparts an oscillatory velocity to electrons that couples with the density ripple to generate a stronger transient transverse current due to the spatial variation of their fields, driving THz radiation. The importance of laser-beamwidth parameters, decentred parameter, amplitude and periodicity of the density structure are discussed for THz emission. By changing the decentred parameter the peak intensity of lasers can be shifted in the transverse direction and a notable change is found in the magnitude of THz field amplitude and its conversion efficiency.