Raman amplification in magnetoactive doped Ⅲ- Ⅴ semiconductors

摘要

Using coupled-mode approach, Raman amplification in a cell consisting of a magnetoactive doped III-V semiconductor is investigated analytically. Assuming that the origin of nonlinear interaction lies in third-order (Raman) susceptibility arising due to nonlinear current density and molecular vibrational polarization of the medium, the threshold condition for the onset of Raman amplification is determined. Well above the threshold intensity (I-0,I-th), the Raman amplification coefficient (g(R)), transmitted intensity of Raman scattered Stokes mode (I-T), and Raman cell efficiency (beta) are also determined. Numerical analysis is made for a representative crystal, viz. n-InSb crystal at 77 K duly irradiated by a pulsed CO2 laser at 10.6 mu m wavelength. The effect of doping concentration (n(0)), external magnetostatic field (B-0) on I-0,I-th, g(R), I-T, and beta are explored in detail with aim to determine suitable values of these (n(0) and B-0) controllable parameters to enhance g(R), I-T and beta at lower I-0,(th), and to establish the suitability of magnetoactive doped III-V semiconductors as hosts for fabrication of efficient Raman amplifiers are established.