Depolarized Holography with Polarization-multiplexing Metasurface

TL;DR

This paper introduces a novel depolarized holography technique using polarization-multiplexing metasurfaces, enabling incoherent-like behavior to improve holographic display quality by reducing speckle noise.

Contribution

It presents a new optical platform integrating metasurfaces with polarization diversity into holography, expanding optimization freedom and enhancing image quality.

Findings

Reduced speckle noise in holographic images

Enhanced image quality through polarization multiplexing

Validated improvements via simulations and experiments

Abstract

The evolution of computer-generated holography (CGH) algorithms has prompted significant improvements in the performances of holographic displays. Nonetheless, they start to encounter a limited degree of freedom in CGH optimization and physical constraints stemming from the coherent nature of holograms. To surpass the physical limitations, we consider polarization as a new degree of freedom by utilizing a novel optical platform called metasurface. Polarization-multiplexing metasurfaces enable incoherent-like behavior in holographic displays due to the mutual incoherence of orthogonal polarization states. We leverage this unique characteristic of a metasurface by integrating it into a holographic display and exploiting polarization diversity to bring an additional degree of freedom for CGH algorithms. To minimize the speckle noise while maximizing the image quality, we devise a fully differentiable optimization pipeline by taking into account the metasurface proxy model, thereby jointly optimizing spatial light modulator phase patterns and geometric parameters of metasurface nanostructures. We evaluate the metasurface-enabled depolarized holography through simulations and experiments, demonstrating its ability to reduce speckle noise and enhance image quality.