REFLECTION OF LIGHT AT 45-DEGREE ANGLE OF INCIDENCE

When light is incident at an angle of 45° on the interface between a transparent medium and an absorbing medium, the complex amplitude reflection coefficients rp and rs for the p and s polarizations are related by rp=rs2. It follows that the intensity reflectances are similarly related, i.e. ℛP = ℛs2 where ℛ = |r|2, as has been previously noted, and that the reflection phase shift for the p polarization is double that for the s polarization, i.e. δp=2δs where δ=arg r, which, as far as can be ascertained, is a new result. Two other interesting consequences of light reflection at 45° are that (1) ellipsometry at this angle determines the omplex reflection coefficient rs in both magnitude and phase, and (2) the angular beam deviation on refraction when both media are transparent is equal to the polarization (or ellipsometric) angle ψ. This is one of the simplest possible relations between propagation directions and polarization directions, i.e. between two properties, one related to geometrical optics and the other to physical optics. © 1979 Taylor & Francis Group, LLC.