Investigation of resonant THz wave generation in plasma density ramp due to Hermite-Cosh-Gaussian lasers

Abstract

This study investigates the generation of terahertz (THz) radiation through the interaction of two Hermite-Cosh-Gaussian (HChG) lasers, co-propagating along the z-axis and polarized along the y-axis, incident obliquely on a plasma. At the beat frequency, the lasers induce a ponderomotive force within the plasma, generating nonlinear velocity and current density, which serve as sources for THz radiation. The research examines THz conversion efficiency in relation to plasma parameters such as normalized propagation distance, tangential plasma ramp, angle of incidence, and plasma frequency, as well as laser parameters including the Hermite polynomial mode index (m) and decentered parameter. The findings highlight potential applications in real-time plasma diagnostics and portable high-frequency sources for wireless communication and medical imaging. This study offers new theoretical insights into the nonlinear interaction of HChG lasers with plasma, advancing THz science and its technological applications.