STIMULATED BRILLOUIN-SCATTERING OF ELECTROMAGNETIC-WAVES PROPAGATING OBLIQUELY IN A MAGNETOACTIVE CENTROSYMMETRIC SEMICONDUCTOR PLASMA

An analytical investigation is made for the stimulated Brillouin scatt ering (SBS) of an electromagnetic wave propagating obliquely with the externally applied magnetic field, in a centrosymmetric, doped semicon ductor plasma. The origin of this nonlinear interaction lies in the th ird-order optical susceptibility arising due to the nonlinear current density and electrostriction of the medium. The magnitude of the third -order nonlinear optical susceptibility determined from our analysis i s found to agree with the theoretically and experimentally quoted valu es. The threshold field for inciting SBS and the corresponding gain co nstant is also identified. The magnetic field and the obliquity of the pump are found to augment the gain constant. The gain constant is fou nd to increase with the scattering angle and is maximum for the backsc attered mode. The transmitted intensity of the scattered mode and Bril louin cell efficiency have also been deduced when the cell length is q uite large compared to the pump wavelength. The cell efficiency is fou nd to be maximum when the magnetic field is applied across the propaga tion direction. The analysis established the possibility of optical ph ase conjugation in a semiconductor plasma and the corresponding thresh old cell length is found to be of the order of nm.