Phase Conjugation via Stimulated Brillouin Scattering in Semiconductor Quantum Plasmas

摘要

Using quantum hydrodynamic model (QHD) an analytical investigation is made for the determination of phase conjugation reflectivity of an electromagnetic wave via stimulated Brillouin scattering in a centrosymmetric, doped semiconductor medium. Effect of Bohm potential on the phase conjugate reflectivity is studied through the quantum corrections in classical hydrodynamic equations. Present paper deals with the qualitative behavior of threshold pump intensity for the onset of OPC-SBS (optical phase conjugation-stimulated Brillouin scattering) and phase conjugate reflectivity with respect to doping concentration with and without quantum corrections. The numerical estimates are made for n-type InSb crystal at 77K duly shined by pulsed 10.6mm CO laser. Phase conjugate reflectivity with and without quantum effect is found to increase with the pump intensity. Consequently OPC-SBS becomes a possible tool in phase conjugate optics even under not-too-high power laser excitation by using moderately doped n-type semiconductors. It is found that the Bohm potential in the electron dynamics enhances the phase conjugate reflectivity. Above the threshold pump field maximum phase conjugate reflectivity equal to 80% is obtained at pump intensities below optical damage threshold of the crystals. The main utility of the analysis lies in establishing the potential of quantum correction through Fermi temperature and Bohm Potential terms for the reduction in the threshold pump intensity and enhancement in OPC-SBS reflectivity of the said process have been realized.