INFRARED QUARTER-WAVE REFLECTION RETARDERS DESIGNED WITH HIGH-SPATIAL-FREQUENCY DIELECTRIC SURFACE-RELIEF GRATINGS ON A GOLD SUBSTRATE AT OBLIQUE-INCIDENCE

One- and two-dimensional high-spatial-frequency dielectric surface-rel ief gratings on a Au substrate are used to design a high-reflectance q uarter-wave retarder at 70 degrees angle of incidence and 10.6-mu m li ght wavelength. The equivalent homogeneous anisotropic layer model is used. It is shown that equal and high reflectances (>98.5%) for the p and the s polarizations and quarter-wave retardation can be achieved w ith two-dimensional ZnS surface-relief gratings. Sensitivities to chan ges of incidence angle, light wavelength, grating filling factor, and grating layer thickness are considered. (C) 1996 Optical Society of Am erica