Translationally invariant metamirrors for spatial filtering of light beams

Abstract

We propose a translationally invariant metamirror for light filtering in reflection. The device consists of athin transverse grating in the micron scale positioned in front of a flat mirror. We analyze the performance ofsuch a photonic metamirror and find a modification of the angular spectrum of the reflected beams, leading toa significant reduction of the beam divergence for particular configurations. This study points toward a typeof optical component, a flat metamirror with a filtering functionality and no alignment requirements, due to itstranslational invariance.