Optical Mode Control by Geometric Phase in Quasicrystal Metasurface

TL;DR

This paper demonstrates how aperiodic geometric phase in quasicrystal metasurfaces enables control over optical spin-dependent modes, leading to potential applications in spin-optical devices.

Contribution

It introduces a novel method to manipulate light-matter interactions in quasicrystals through geometric phase engineering for spin-dependent optical control.

Findings

Observation of spin-controlled modes in quasicrystal metasurfaces

Demonstration of polarization helicity dependence and optical spin-Hall effect

Experimental verification of spin-flip behavior in visible spectrum

Abstract

We report on the observation of optical spin-controlled modes from a quasicrystalline metasurface as a result of an aperiodic geometric phase induced by anisotropic subwavelength structure. When geometric phase defects are introduced in the aperiodic structured surface, the modes exhibit polarization helicity dependence resulting in the optical spin-Hall effect. The radiative thermal dispersion bands from a quasicrystal structure were studied where the observed bands arise from the optical spin-orbit interaction induced by the aperiodic space-variant orientations of anisotropic antennas. The optical spin-flip behavior of the revealed modes that arise from the geometric phase pickup was experimentally observed within the visible spectrum by measuring the spin-projected diffraction patterns. The introduced ability to manipulate the light-matter interaction of quasicrystals in a spin-dependent manner provides the route for molding light via spin-optical aperiodic artificial planar surfaces.