Phase conjugation in weakly piezoelectric magnetized semiconductor-plasmas

Abstract

The occurrence of optical phase conjugation via stimulated Brillouin scattering (OPC-SBS) in weakly piezoelectric III–V semiconductor plasmas subjected to a large magnetostatic field under off-resonant transition regime has been explored theoretically. The reflectivity of the phase conjugate wave is dependent upon the Brillouin susceptibility and can be significantly enhanced through n-type doping of the crystal and the simultaneous application of a magnetostatic field. Moreover, the threshold pump intensity required for the occurrence of SBS in the crystal with finite optical attenuation can be considerably diminished through proper selection of the doping concentration and magnetostatic field. Consequently, OPC-SBS becomes a possible tool in phase-conjugate optics even under not-too-high power laser excitation by using doped n-type semiconductors kept under the influence of a large magnetostatic field. Numerical estimates made for n-InSb crystal at 77 K duly irradiated by a nanosecond pulsed 10.6 µm CO2 laser reveal that high OPC-SBS reflectivity can be achieved at excitation intensities below the optical damage threshold if the semiconductor crystal is used as an optical waveguide with an interaction length of a few millimetres.