Thermal emission characteristics of an anisotropic scattering medium layer with gradient index

By combining the Monte Carlo method and curved ray tracing technique, the thermal emission characteristics of an anisotropic scattering semitransparent medium with gradient refractive index were analyzed. The semitransparent and specular emerging surface of the medium layer was parallel to an opaque and diffuse substrate wall. The influence of the scattering albedo and scattering phase function to the apparent emittance was investigated. The results show that the influence of the scattering to the apparent emission characteristics is important. In the medium with linear refractive index distribution, when strong scattering happens, the apparent emission would reduce with the increase of the optical thickness of the medium. This phenomenon is quite different from that in conventional semitransparent bodies.