Metasurface orbital angular momentum holography

TLDR

Metasurfaces enable subwavelength control of light, making them ideal for planar phase holograms that could boost optical communication bandwidth, yet conventional holograms lack orbital angular momentum selectivity, preventing their use as information carriers. This study demonstrates metasurface orbital angular momentum holography by employing GaN nanopillar meta-holograms with discrete spatial frequency distributions. The authors achieve OAM selectivity through meta-holograms composed of GaN nanopillars arranged with discrete spatial frequency distributions. The OAM‑multiplexing enables lensless reconstruction of diverse OAM‑dependent holographic images, paving the way for ultrahigh‑capacity holographic devices that exploit this multiplexing.

Abstract

Abstract Allowing subwavelength-scale-digitization of optical wavefronts to achieve complete control of light at interfaces, metasurfaces are particularly suited for the realization of planar phase-holograms that promise new applications in high-capacity information technologies. Similarly, the use of orbital angular momentum of light as a new degree of freedom for information processing can further improve the bandwidth of optical communications. However, due to the lack of orbital angular momentum selectivity in the design of conventional holograms, their utilization as an information carrier for holography has never been implemented. Here we demonstrate metasurface orbital angular momentum holography by utilizing strong orbital angular momentum selectivity offered by meta-holograms consisting of GaN nanopillars with discrete spatial frequency distributions. The reported orbital angular momentum-multiplexing allows lensless reconstruction of a range of distinctive orbital angular momentum-dependent holographic images. The results pave the way to the realization of ultrahigh-capacity holographic devices harnessing the previously inaccessible orbital angular momentum multiplexing.