Terahertz radiation generation by a super-Gaussian laser pulse in a magnetized plasma

Abstract

We investigate the enhanced terahertz (THz) field generation via transverse wakefield by a super-Gaussian laser pulse in a magnetized plasma. Due to the “hat-on-top” intensity profile, the super-Gaussian laser pulse may be better for excitation of nonlinearities in plasmas. We utilize the special properties of the super-Gaussian laser pulse to generate THz current in a magnetized plasma. The transverse wakefield is significantly higher for the super-Gaussian laser pulse in comparison to the Gaussian laser pulse. The magnetic field provides a resonance to focus the THz fields. The transverse current at THz frequency can also be controlled by adjusting the index of the super-Gaussian laser pulse. We report about ten-fold enhanced THz field from this mechanism by using the super-Gaussian laser pulse. We observe that the stable THz is generated with a maximum field strength of ∼1 GV/cm and a relatively broad spectrum extending out to 50 THz, which corresponds to the conversion efficiency in order of 10−2 for a magnetic field strength of 1 T. The efficiency of this process may be optimized and controlled by the laser and plasma parameters, which is of high interest for various applications such as THz extreme nonlinear optics.