Dynamics of Hermite–Gaussian laser beam in plasma and terahertz generation

Abstract

In the present work, the dynamical study of a Hermite–Gaussian (HG) laser beam propagating through plasma with relativistic nonlinearity has been carried out. Furthermore, the dependency of THz generation on the HG laser dynamics has also been investigated. Self-focusing of laser beam inside plasma is achieved due to the modification in electron’s rest mass due to their motion at relativistic velocities. The coupled differential equations obtained using the method of moment determines the variation in spot size of laser beam and have been solved numerically. The laser beam propagating through plasma excites the plasma wave and the nonlinear coupling of HG beam and plasma wave generates THz radiation. It has been observed that THz generation strongly depends upon the variation of spot size, TEM modes, plasma density and intensity of laser beam. Furthermore, the self-trapping of HG laser beam has also been studied.