Radiation Entropies in Beam-Splitting and Application to Solar Radiation

Abstract

The spectral specific intensities of energy radiation split into two parts by a thin beam-splitter are given. The spectral specific intensity of incident entropy radiation L₀(ν) and those of split entropy radiation L₁(ν) and L₂(ν) satisfy an inequality L₀(ν)<L₁(ν)+L₂(ν). It is shown that the radiation entropy always increases in beam-splitting. As an application, solar radiation incident upon the earth is considered.