Coupled-Wave Analysis Of Two-Dimensional Dielectric Gratings

Diffraction by two-dimensional surface-relief dielectric gratings are analyzed using rigorous three-dimensional vector coupled-wave approach. The method applies to arbitrary plane wave angle of incidence, wavelength, and polarization. In the resulting conical diffraction, the input TE and TM polarization are coupled and the diffracted orders are, in general, elliptically polarized. Diffraction characteristics of two-dimensional binary gratings are presented. Ultrahigh spatial-frequency gratings (grating period less light wavelength) are shown to exhibit polarization independent antireflection behavior (zero-reflectivity).