Fresnel reflection at normal incidence r = (n_1 - n_2)/(n_1 + n_2); Mobius linear-fractional

Fresnel-reflection framework at normal incidence (Fresnel 1823 Memoire sur la loi des modifications de la lumiere). Setup: at the planar interface between two transparent dielectrics with refractive indices n_1, n_2, the amplitude…