Comparison between polarization measurements and model calculations of cenosphere surfaces, with different depolarization properties and different coverage

摘要

Polarization measurements in the infrared region have earlier been done on cenosphere surfaces. These surfaces have been constructed so that they have almost completely depolarized reflected and emitted radiations. It was also possible to construct the surface so that a desired normal incidence reflectivity and emissivity was achieved. The measurements were performed by measuring emissivity as a function of the emissive angle, from 5° to 85°, and for different polarization angles. From these angle measurements the polarization parameters such as Degree of Linear Polarization (DoLP) and Θ can been calculated. In this work, model calculations of scattering from a rough surface consisting of cenospheres are performed, using Monte Carlo calculations on a geometrical optical model. The model calculations have given good results and can explain both the depolarization and the possibility to determine the emissivity, from the cenosphere surface, by changing the amount of gold deposited on the surface.