Modulational interactions in magnetised piezoelectric semiconductor plasmas
School of Studies in Physics, Vikram University,
Ujjain-456 010, Madhya Pradesh, India
Revised: 17 December 1999
Published online: 15 August 2000
Based on hydrodynamic model of plasmas an analytical investigation of frequency modulational interaction between copropagating high frequency pump and acoustic mode and consequent amplification (steady-state and transient) of the modulated waves is carried out in a magnetised piezoelectric semiconductor medium. The phenomenon of modulational amplification is treated as four wave interaction process involving cubic nonlinearity of the medium. Gain constants, threshold-pump intensities and optimum-pulse duration for the onset of modulational instabilities are estimated. The analysis has been performed in non-dispersive regime of the acoustic mode, which is one of the preconditions for achieving an appreciable initial steady-state growth of the modulated signal wave. It is found that the transient gain constant diminishes very rapidly if one chooses the pump pulse duration beyond the maximum gain point. Moreover, the desired value of the gain can be obtained by adjusting intensity and pulse duration of the pump and doping concentration of the medium concerned.
PACS: 52.35.Mw – Nonlinear waves and nonlinear wave propagation (including parametric effects, mode coupling, ponderative effects, etc.) / 42.65.Ky – Harmonic generation, frequency conversion / 42.50.Md – Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000