Abstract
Abstract
Dielectric Fourier metasurfaces—thin layers of strongly refracting transparent materials with periodic surface nanoreliefs—are capable of versatile flat-optical functionalities, including anomalous refraction in up to near-grazing directions. Describing the reliefs by a few Fourier coefficients, one can straightforwardly optimize them numerically or, eventually, analytically in terms of the Rayleigh hypothesis. We demonstrate that silicon Fourier metasurfaces supporting anomalous refraction in near-grazing directions can be employed as efficient optical Y-junction switches. Operating in the vicinity of a certain diffraction order cutoff, they can drastically alter the direction of outgoing light due to subtle variations of the optical setup. As examples, we show the possibility to deflect 70%–80% of the power of green light by more than 150 degrees when the incoming beam is inclined by only 2 degrees, or when the relative substrate permittivity is varied by 0.1. We also evaluate the prospects of metasurfaces made of other weaker-refracting transparent materials.
Funder
Russian Science Foundation
Subject
Atomic and Molecular Physics, and Optics,Electronic, Optical and Magnetic Materials