Spectral optical vortex modulation from geometric phase diamond metasurface arrays

Abstract

Agile management of the optical orbital angular momentum encompasses temporal, spatial, and spectral aspects that, once combined, offer new perspectives in our way to manipulate light. To date the spectral control is mainly limited to tunable operating wavelength and polychromatic capabilities. Recently, a multispectral approach has been proposed [Phys. Rev. Lett. 121, 213901 (2018)] to achieve independent orbital angular momentum state control on multiple spectral channels. Here we report on the design, fabrication and implementation of a solid-state multispectral approach that consists of arrays of optical diamond micro-metasurfaces. Obtained device exhibits superior performances with respect to the original attempt, both regarding the spectral vortex purity, the ability to deal with high photon flux, and the orbital angular momentum diversity across the spectrum. These results motivate further development of metasurface-based integrated spin–orbit photonics technologies.