An angle-independent Frequency Selective Surface in the optical range.

We suggest and numerically demonstrate a design for Frequency Selective Surfaces (FSS) operating in the optical (visible and near-infrared) range. The position and width of the FSS bandpass do not depend on the angle of incidence and polarization state of the incoming light, allowing high transmission at any angle. The FSS is formed by annular apertures perforated in a metal film and arranged in a square array. Angle- and polarization-independent transmission properties are demonstrated for silver. These results can be extended to other metals as well as to other frequency domains.