Angle of incidence of minimum reflectance of a dielectric-conductor interface for incident unpolarized or circularly polarized light.
The angle of incidence ϕ=ϕ<sub>u min</sub> of minimum reflectance for incident unpolarized or circularly polarized light at a dielectric-conductor interface is determined for any complex relative refractive index N=(n,k), and contours of constant ϕ<sub>u min</sub> in the nk plane are presented. The minimum reflectance R<sub>u min</sub> at ϕ<sub>u min</sub> is also plotted as a function of the polar angle 0≤θ=arg(N)≤90° along each constant ϕ<sub>u min</sub> contour. Also presented are families of R<sub>u</sub>-versus-ϕ curves for values of complex N at θ=30°, ϕ<sub>u min</sub>=45° to 85° in steps of 10°, and values of complex N at ϕ<sub>u min</sub>=75°, θ=0° to 90° in steps of 10°. Finally, a nonpolarimetric method for the determination of n and k of optical materials, which is based on measurements of ϕ<sub>u min</sub> and the normal-incidence reflectance R<sub>0</sub>, is proposed.