Abstract

An absorbing substrate of complex refractive index n₂−jk₂ can be coated by a transparent thin film of refractive index n₁ and normalized thickness ζ so that the ratio of complex reflection coefficients for the p and s polarizations of the film-covered substrate ρ is the inverse of that of the film-free substrate $\bar{\rho }$ at a given angle of incidence ϕ. A pair of parallel (metallic) mirrors, one uncoated and the other coated with a ρ-inverting layer, causes a beam displacement without change of polarization and with a certain net reflectance (insertion loss) ℛ. In this paper the constraint on n₁, n₂, k₂ for ρ inversion $(\rho \bar{\rho }=1)$ is represented by a family of constant −n₁ contours in the n₂k₂ plane at ϕ = 45, 60, and 75°. Along each solution curve, ζ and ℛ are also plotted vs n₂ at constant n₁. Analysis of the effect of small errors of incidence angles, film refractive index, and thickness is presented for two specific designs using Al mirrors at 650 and 950 nm.

© 1987 Optical Society of America

Constraint on the optical constants of a film–substrate system for operation as an external-reflection retarder at a given angle of incidence

R. M. A. Azzam and Bruce E. Perilloux
Appl. Opt. 24(8) 1171-1179 (1985)

Inverting the ratio of the complex parallel and perpendicular reflection coefficients of an absorbing substrate using a transparent thin-film coating

R. M. A. Azzam
J. Opt. Soc. Am. A 1(7) 699-702 (1984)

Antireflection of an absorbing substrate by an absorbing thin film at normal incidence

R. M. A. Azzam, E. Bu-Habib, J. Casset, G. Chassaing, and P. Gravier
Appl. Opt. 26(4) 719-722 (1987)

Achieving a given reflectance for unpolarized light by controlling the incidence angle and the thickness of a transparent thin film on an absorbing substrate: application to energy equipartition in the four-detector photopolarimeter

R. M. A. Azzam and Kurt A. Giardina
Appl. Opt. 31(7) 935-942 (1992)

Complex reflection coefficients for the parallel and perpendicular polarizations of a film–substrate system

R. M. A. Azzam and M. Emdadur Rahman Khan
Appl. Opt. 22(2) 253-264 (1983)