Third Harmonic Generation of Hermite-cosh-Gaussian laser Beam

Abstract

Abstract In present study we have investigated the third harmonic generation (THG) of self-focused Hermite-cosh-Gaussian (HchG) laser beam, propagating through plasma. When intense short pulse laser propagates through plasma results ponderomotive force on electrons due to which electrons move away from the axial region, creating a low density plasma region. Due to electrostatic force, electrons gain oscillatory velocity and results density perturbation. Density oscillations at frequency 2ω1 couple with oscillatory velocity of electrons, at the fundamental frequency of incident laser result THG. Due to phase mismatch with the incident pulse, the third harmonic pulse is of smaller amplitude. Wiggler field satisfy the resonance condition by providing additional momentum to the photon of third harmonic pulse and this result increase in the normalized amplitude of third harmonic pulse. In the present study the study of beam width parameter with normalized propagation distance at optimum values of different laser parameters has been studied. We derived the coupled differential equation for the normalized amplitude, A'30/A 10, of third harmonic pulse. We analysed the efficiency of third harmonic pulse with ξ at optimum values of normalized intensity of fundamental laser.