High Gain Coefficient Parametric Amplification of Optical Phonon Mode in Magnetized AIIIBV Semiconductor Plasmas

Abstract

Using the hydrodynamic (fluid) model of plasmas, we have studied the threshold and gain characteristics of parametric amplification of optical phonon mode in magnetized AIIIBV semiconductor plasmas. The origin of nonlinear interaction is assumed to lie in second-order nonlinearity arising due to nonlinear coupling of pump wave, optical phonon and signal modes in the medium. Theoretical formulation has been carried out with the help of coupled mode theory under rotating-wave approximation. Numerical estimates have been made for a representative magnetized doped AIIIBV semiconductor crystal (viz. n-InSb) irradiated by a pulsed 10.6 μm CO2 laser. The analysis enables us to choose one of the three achievable resonance conditions: (electron–cyclotron frequency ~ pump frequency, coupled cyclotron– plasmon frequency ~ Stokes frequency, coupled cyclotron–plasmon frequency ~ optical phonon frequency), at which threshold pump amplitude reduces, whereas parametric gain coefficient enhances nearly hundred times. The lowering of threshold and enhancement of parametric gain coefficient, in AIIIBV semiconductors under proper selection of doping concentration and externally applied magnetic field, confirm the chosen nonlinear medium as a potential candidate material for fabrication of optical parametric amplifier with enhanced gain coefficient.