Stimulated Brillouin scattering in a centrosymmetric semiconductor plasma

Abstract

Based upon the electromagnetic treatment, stimulated Brillouin scattering (SBS) in a centrosymmetric, doped semiconductor which is subjected to a transverse magnetic field is investigated analytically. The origin of this nonlinear interaction is considered to be found in the third order optical susceptibility arising due to non-linear current density and acousto-optic polarization of the medium. The threshold condition is obtained for the onset of the SBS. The effective Brillouin susceptibility and the resulting gain is determined using the coupled mode scheme. Using the effective third order polarization so achieved, authors have also calculated the transmitted intensity and Brillouin cell efficiency. The effect of magnetic field and doping on threshold field and Brillouin gain is also studied. Numerical estimations are made for n-InSb at 77 K duly shined by a pulsed 1 0 . 6 ~ CO, laser. The gain constant is significantly enhanced under high power pulsed excitation below the damage threshold and under the influence of a transverse magnetostatic field when the cyclotron frequency is less than the acoustic wave frequency. The required threshold electric field for the onset of the SBS process is also reduced significatly in the presence of a magnetostatic field. The minimum cell length required to achieve optical phase conjugation is found to be 0.45 pm.

Phase conjugation in magnetized semiconductors by stimulated Brillouin scattering

“…This complies with the well known fact [12] that in all crystalline solids, SBS arises from the finite electrostriction of the medium caused by the coupling of the pump photons (ω p , k p ) with acoustic phonon modes (ω a , k a ). The response of electrons and nuclei to the laser irradiation changes the dielectric constant of the medium.…”

“…The growing technological potential of phase conjugate mirrors in the infrared regime warrants experimental investigation of SBS in the InSb crystal-CO laser system. Recently, Jat et al [12] studied the phenomena of SBS in a semiconductor plasma medium following classical electromagnetic treatment. In their analysis [12], the origin of the Brillouin susceptibility has been assumed to be in the nonlinear coupling among the three interacting waves and the finite acousto-optical polarization.…”

“…Recently, Jat et al [12] studied the phenomena of SBS in a semiconductor plasma medium following classical electromagnetic treatment. In their analysis [12], the origin of the Brillouin susceptibility has been assumed to be in the nonlinear coupling among the three interacting waves and the finite acousto-optical polarization. On the contrary, the present investigation deals with near band gap resonant photoinduced direct band-to-band electron transitions in an intrinsic InSb crystal assumed to be illuminated by a 6 µm pulsed CO laser and the shift in the energy level due to Landau level splitting has been incorporated quantum mechanically.…”

Phase conjugation in weakly piezoelectric magnetized semiconductor-plasmas

“…In this configuration, the OPC-SBS reflectivity increases linearly with pump intensity. The numerical analysis of Jat et al [24] for a doped n-InSb crystal illuminated by a 10.6 mm CO 2 laser shows an increase in transmitted intensity (and hence the so-called Brillouin cell efficiency) with increasing input intensity; no saturation behavior in the OPC-SBS reflectivity was observed. Journal of Modern Optics 941 reflectivity in non-centrosymmetric semiconducting crystals is much larger than that in centrosymmetric semiconductors at same pump excitation intensity.…”

“…The characteristic dependence of OPC-SBS reflectivity on pump intensity, magnetic field and doping concentration in n-InSb irradiated with a 10.6 mm CO 2 laser is studied using Equations (23) and (24) for L51. The results are plotted in Figures 3-5.…”