Inverse designed full-Stokes polarimetric metasurface with simultaneous wavefront sensing for visible light

TL;DR

This paper presents an inverse-designed metasurface capable of full-Stokes polarimetry and wavefront sensing in a single, continuous aperture, enabling compact, multifunctional optical diagnostics with high accuracy.

Contribution

It introduces a novel inverse design approach that integrates polarization and wavefront sensing in a continuous metasurface, surpassing traditional aperture-sharing limitations.

Findings

Achieved a polarization reconstruction error of 0.046 on the Poincaré sphere.

Enabled simultaneous wavefront tilt detection and polarization mapping in a compact device.

Utilized neural networks for peak identification and hardware correction.

Abstract

Metasurfaces have emerged as a powerful platform for compact optical sensors by replacing bulky lenses with flat arrays of subwavelength nanostructures. In precision optical metrology, the simultaneous mapping of a beam's polarization state and wavefront is crucial for real-time diagnostics of stress-induced birefringence and surface flatness. To achieve this in a compact footprint, existing metasurfaces typically partition their aperture into discrete zones, which inherently restricts the light-gathering efficiency and numerical aperture of the system. Here we demonstrate an inverse-designed metasurface that integrates full-Stokes polarimetry and Shack-Hartmann wavefront sensing within a single, continuous aperture in the visible spectrum. By leveraging an adjoint optimization approach to independently control the geometry and rotation of each nanostructure, we break the aperture-sharing paradigm and utilize the entire pixel area for all channels. When coupled with a shallow neural network to automate peak identification and correct for hardware non-idealities, our device yields a mean polarization reconstruction error of only 0.046 across 100 test states on the Poincar\'e sphere, while simultaneously maintaining the precise focal-spot tracking required for sensitive wavefront tilt detection. This work highlights the capacity of inverse design to generate multifunctional, non-intuitive flat optics that outperforms its traditional counterparts.