Enhanced THz generation by Hermite-cosh-Gaussian chirped laser in static magnetized plasma

Abstract

The investigation of tuneable and energy-efficient terahertz (THz) generation has become a prominent field of study due to its significant ramifications in various disciplines, including chemical analysis and medical research. This study selects two co-propagating Hermite-cosh-Gaussian (HchG) laser beams with positively chirped frequencies for analysis. The laser beam exhibits interaction with a collisionless underdense plasma in the presence of a static transverse magnetic field. The interaction between laser and plasma exhibits nonlinear characteristics, leading to the creation of THz radiation with high energy efficiency. The primary objective of this study is to conduct an analytical examination of the correlation between THz conversion efficiency, normalised transverse distance, and plasma frequency. Additionally, the analysis will consider various laser parameters, including the Hermite polynomial mode index (s), decentred parameter (a), and frequency chirp (b). The results show that in off-resonant condition THz conversion efficiency quickly decreases and approaches to zero for normalised THz frequencies. The observed phenomenon entails an augmentation in the normalized amplitude of terahertz (THz) waves, accompanied by a displacement of the peak towards greater normalized transverse distance values. This occurrence is contingent upon the variation of the Hermite polynomial mode index within the range of \(0 \, to \, 2.\) As the chirp parameter (b) is increased from \(0.0011 \, to \, 0.0099\), the normalised terahertz (THz) amplitude exhibits an increase with respect to the normalised transverse distance for values of \(s\) equal to \(\text{0,1} \, and \, 2.\) The proposed methodology demonstrates significant use in generating high-intensity, adjustable, and energy-efficient terahertz (THz) radiation sources through the manipulation of the decentred parameter and Hermite polynomial mode index values.