Complete Absorption of Light by Thin Metal Films

Abstract

Reflectances of non-opaque aluminium films were measured from the substrate side as a function of angle of incidence. For the p-polarization there is a maximum reflectance near the critical angle for the substrate; for a certain range of Al thicknesses this is followed by a sudden drop which can be to zero reflectance giving complete absorption. This effect can be predicted from thin film theory but has not previously been noted.