NONLINEAR ABSORPTION AND REFRACTIVE-INDEX OF A RAMAN SCATTERED MODE IN MAGNETOACTIVE CENTROSYMMETRIC SEMICONDUCTOR PLASMAS

With the aid of a hydrodynamic model of a plasma, a detailed analytica l investigation is made of the Raman instability of the Stoke's compon ent of the scattered wave in an obliquely magnetised (with respect to the direction of propagation) centrosymmetric semiconductor. The origi n of the stimulated Raman scattering process lies in the third-order n onlinear optical susceptibility arising due to the induced nonlinear c urrent density and the interaction of the pump wave with the density f luctuations generated within the medium. The agreement in magnitude fo r third-order Raman susceptibility between our calculated values and t he experimental as well as other theoretical values is found to be goo d. Using the coupled mode theory of plasmas the total refractive index and absorption coefficient are determined via the effective susceptib ility. The magnetic field and effective electric field are found to au gment the refractive index. The absorption coefficient is found to be minimum when the pump is inclined at an angle of 12 degrees to the mag netic held. The absorption coefficient reaches its minimum for the bac kscattered mode. The analysis establishes that a large nonlinear refra ctive index and a small absorption coefficient can easily be obtained in a magnetised centrosymmetric crystal which proves its potential as candidate material for fabrication of cubic nonlinear devices.