Hot carrier effects on steady-state and transient Brillouin gain coefficients of semiconductor magneto-plasmas

Abstract

Using coupled mode approach, an analytical investigation of hot carrier effects (HCEs) of pump wave on (steady-state and transient) Brillouin gain coefficients of semiconductor magneto-plasmas is made under various geometrical configurations. The threshold condition for exciting transient stimulated Brillouin scattering phenomenon is estimated. Numerical calculations are made for n-InSb crystal – CO2 laser system. Efforts are made to obtain enhanced values of Brillouin gain coefficients and lower threshold intensity by suitably choosing plasma and cyclotron frequencies around resonances. HCEs of intense pump wave modifies the momentum transfer collision frequency of carriers and consequently the nonlinearity of the Brillouin medium, which in turn (i) lowers threshold intensity, (ii) enhances Brillouin gain coefficients, (iii) shifts the enhanced Brillouin gain spectrum towards smaller values of magnetic field, and (iv) widens the range of magnetic field at which peak of Brillouin gain spectrum (around resonance) occurs. The inclusion of HCEs in the analysis leads to better understanding of laser-plasma interactions and validate the possibility of chosen Brillouin medium as a potential candidate material for the fabrication of widely tunable and efficient Brillouin amplifiers and oscillators.