Abstract

Zero reflectivity (unity transmissivity) surfaces on materials are useful for eliminating unwanted reflections. If the substrate is lossy and sufficiently thick, the incident radiation is totally absorbed. Using an impedance matching approach, the filling factor and groove depth of a rectangular-groove grating to produce zero reflectivity are calculated for lossless (dielectric) and lossy (metallic) substrates. These gratings are equivalent to a single homogeneous layer in the long-wavelength limit. The analysis is applicable to both TE and TM polarization and any angle of incidence. The antireflection behavior is verified for the gratings using the rigorous (without approximations) coupled-wave analysis of grating diffraction. Example zero-reflectivity gold gratings for an incident free space wavelength in the 0.44-12.0-μm range are presented.

© 1987 Optical Society of America