Physica B 328 (2003) 255–263 Parametric amplification in magnetized diffusive semiconductor plasmas S. Ghosh*, Giriraj Sharma 1 , M.P. Rishi School of Studies in Physics, Vikram University, Ujjain, MP-456-010, India Received 22 March 2002; received in revised form 15 October 2002 Abstract Assuming that the origin of the nonlinear interaction lies in the second-order optical susceptibility w ð2Þ arising from the diffusion-induced nonlinear current density, and using straight-forward coupled mode theory, the parametric amplification is analytically investigated in a magnetized diffusive semiconductor plasma. The threshold value of the pump electric field E 0th is obtained which is found to decrease with rising magnetic field. We found minimum value of E 0th at wave number k ¼ 7:45  10 7 m 1 (say k m ). This k m is greatly influenced by carrier concentration and diffusion coefficient of the medium. The parametric gain constant is also obtained. It is found that gain maximizes at very low magnetic field (B6 kG), which may drastically reduce the fabrication cost of parametric amplifier based on this interaction. r 2002 Elsevier Science B.V. All rights reserved. PACS: 52.35.Mw; 78.70.Hp; 42.70.Nq Keywords: Parametric interactions; High-frequency effects; Acousto-optical effects; III–V semiconductors 1. Introduction Parametric interaction (PI) of an intense laser beam (hereafter called ‘pump’) with matter results into generation of waves at new frequencies through controlled splitting or mixing of the waves which may undergo amplification/attenuation depending on the material properties and the applied field geometry. Thus there are two distinct viewpoints of the said interaction: a material properties and a wave propagation characteristics. These phenomena can well be explained in terms of bunching of the free carriers present in the medium under the influence of the fields applied externally and those associated with the generated wave [1]. Thus any mechanism influencing the carrier bunching is expected to modify the linear and nonlinear properties of the medium and hence the dependent phenomena. Since carrier bunching induces a concentration gradient in the medium, their diffusion becomes inevitable and thus can play a crucial role in parametric processes. The breakdown of the superposition principle in a nonlinear medium leads to interactions between *Corresponding author. Tel.: +91-0734-511571; fax: +91- 734-514-276. E-mail address: drsanjayghosh@rediffmail.com (S. Ghosh). 1 S.R.J. Government Girls’ College, Neemuch, MP-458-441, India. 0921-4526/03/$-see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0921-4526(02)01795-7