Density of States Effects on Emission and Scattering of Photons in Plasmas

Abstract

Plasma supports electromagnetic waves propagation for frequencies higher than plasma frequency but features dielectric permittivity less than 1. This property leads to photon density of states (DOS) lower than in vacuum and should result in subnatural spectral linewidths, sub-Planckian spectrum of thermal radiation, and in sub-Rayleigh photon scattering as well as in lower inelastic photon scattering including Raman scattering in molecular and crystalline structures. We emphasize the basic character of these phenomena though absolute values of corrections from this property of plasmas in many real experiments may appear to be small as compared to other factors. We found that dissipative losses when being taken into account make possible DOS effects smaller though not vanishing and additionally bring about indefinite growth of DOS in the low-frequency limit.