Transmissive phase retarder

Abstract

The present invention is a transmissive phase retarder in which reflection of an incident beam of light is substantially reduced and in which the incident light experiences a phase retardation between the s- and p-plane polarization components of the transmitted light. The transmissive phase retarder includes a transmissive substrate, such as glass, and a plurality of superimposed thin film transparent layers on the transmissive substrate. The adjacent layers of the superimposed thin film layers are made of materials of substantially different indices of refraction, n.sub.i. The optical thicknesses, f.sub.i, of the layers are prescribed so that they satisfy the transmission and retardation requirements in order to produce both maximum transmission and a specified phase shift, .PHI..sub.i, in the s- and p-plane polarization components of the transmitted light for a broadband range of wavelengths at a specified angle of incidence, .theta..sub.os, by minimizing a merit function by adjusting the optical thickness, f.sub.i, of each layer wherein the merit function, ##EQU1## where .PHI.(f.sub.i), and T.sub.s (f.sub.i) and T.sub.p (f.sub.i) are standard functions for determining the phase retardation, the transmission of the s-plane polarization component and the transmission of the p-plane polarization component of transmitted light, respectively, for a particular set of wavelengths, .lambda..sub.i.

Dependencies are inferred from the claim text.