The Impact of Surface Roughness on Light Absorption

We report on a comprehensive study carried out to reveal the impact of surface roughness on the incident light absorption. In practice, we have used analytical approach of solving Maxwell equations by modifying boundary conditions that take into account the surface roughness in metallic or dielectric films. Our approach reveals interference linked terms that modify the absorption dependence on the surface roughness characteristics, light wavelength,polarization and incidence angle. We have discussed the limits of our approach that hold valid from optics to microwave region. Polarization and angular dependences of roughness induced absorption are revealed. Existence of an incident angle and a wavelength for which the absorptance of rough surface becomes equal to the absorptance of flat surface is predicted. Relaying on this phenomena a method of determination of roughness correlation length is suggested.