PARTIAL COHERENCE THEORY OF THIN-FILM RADIATIVE PROPERTIES

A new approach based on the partial coherent theory of light is introduced to predict the radiative properties of a thin film. General expressions obtained for the normal reflectance and transmittance of a thin film not only degenerate into the limiting results of the wave and the geometric optics in the coherent and incoherent cases, but also apply for all partial coherent states between the limits. The key element in the formulation is the complex degree of coherence, for which a general integral expression is obtained and further approximated algebraically for nearly monochromatic radiation. Limiting criteria and regime maps are established to demonstrate the range of applications for the various methods.