Physical Basis for the Maximum Thermal Radiation Emission between Materials

Abstract

An analytic basis for the limit on intra-media thermal radiation transport has been obtained as a simple function of temperature and material optical properties (n,k). It is shown that optical parameters determine the maximum radiative energy transfer rate by altering media radiative state density and energy density. Quantitative analysis shows that intra-media radiative transfer rates may exceed the radiation into free space as described by the Stephan-Boltzmann equation by several orders of magnitude. The frequency dependence of the optical properties further alters the expected blackbody spectral dependence. This generalized formulation of the limit to thermal radiation transfer in terms of media optical properties expands the understanding and future potential of radiative processes.