Maximum minimum reflectance of parallel-polarized light at interfaces between transparent and absorbing media

The pseudo-Brewster angle ϕpB, of minimum reflectance ℛpm for the parallel (p) polarization, of an interface between a transparent and an absorbing medium is determined by Im{(∊ − u)[1 − (1 + ∊−1)u]2} = 0, where ∊ is the complex ratio of dielectric constants of the media and u = sin2ϕpB. It is shown that, for a given value of the normal-incidence amplitude reflectance |r|, there is an associated normal-incidence phase shift, δ = δmm, that leads to maximum minimum parallel reflectance, ℛpmm. We determine δmm, ℛpmm, ϕpBmm as functions of |r|. We find that, as |r| increases from 0 to 1, δmm decreases from 90° to 0, ℛpmm/|r|2 increases from 0 to 1, and the associated ϕpBmm decreases from 45° to 0, all monotonically.