The net differential phase shift introduced between the orthogonal p and s linear polarizations after four successive total internal reflections inside an in-line chevron dual-Fresnel-rhomb retarder is a function of the first internal angle of incidence φ and prism refractive index n. Retardance of (i.e., ) is achieved with minimum angular sensitivity when and . Several optical glasses with this refractive index are identified. For Schott glass SF66 the deviation of from is over a wave length range of in the visible and near-IR spectrum. For a SiC prism, whose totally reflecting surfaces are coated with an optically thick film, at two wavelengths: and . This coated prism has a maximum retardance error of
(0.5 to ) in the visible, near-, and mid-IR spectral range. Another mid-IR retarder uses a Si prism, which is coated by an optically thick silicon oxynitride film of the proper composition, to achieve retardance that differs from by over the spectral range.
© 2008 Optical Society of America
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