Scattering and Propagation of Electromagnetic Waves in Bounded Parametrically Modulated Media

摘要

Scattering and propagation of electromagnetic waves in bounded, parametrically modulated media are investigated. The particular case is examined where the permittivity of a dielectric medium is modulated in a wave-like manner in time and space. Such a medium represents a linearized description for nonlinear effects due to a high-intensity 'pump' wave, valid for incident waves of low-intensity. The investigation starts with the analysis of dispersion relations for the determination of temporal and spatial instabilities of waves propagating in an active distributed, parametrically modulated medium. It is found that, in a medium with basic dispersion, four types of parametric interactions are possible, namely: a contra-flow, active interaction which results in temporal instability; a co-flow, active interaction which results in spatial instability; a contra-flow, passive interaction; and finally, a co-flow, passive interaction. The last two types of interaction are temporally as well as spatially stable. The boundary value problems of parametric media of finite extent are formulated for the cases of temporally stable interactions, so that a steady state analysis is permitted. (Author)