Inverse Designed Extended Depth of Focus Meta-Optics for Broadband Imaging in the Visible

TL;DR

This paper introduces an inverse-designed meta-optic with extended depth of focus and broadband imaging capabilities in the visible spectrum, maintaining high efficiency and invariant PSF across a wide bandwidth.

Contribution

The work presents a novel inverse design approach for a high-NA EDOF meta-optic with broadband, invariant PSF, outperforming traditional phase mask designs.

Findings

Achieves high focusing efficiency (~0.44 NA) across the entire visible spectrum.

Maintains a highly invariant PSF over ~290nm bandwidth, improving image quality.

Demonstrates broadband imaging with a compact, 1mm, f/1 meta-optic.

Abstract

We report an inverse-designed, high numerical aperture (~0.44), extended depth of focus (EDOF) meta-optic, which exhibit a lens-like point spread function (PSF). The EDOF meta-optic maintains a focusing efficiency comparable to that of a hyperboloid metalens throughout its depth of focus. Exploiting the extended depth of focus and computational post-processing, we demonstrate broadband imaging across the full visible spectrum using a 1 mm, f/1 meta-optic. Unlike other canonical EDOF meta-optics, characterized by phase masks such as a log-asphere or cubic function, our design exhibits a highly invariant PSF across ~290nm optical bandwidth, which leads to significantly improved image quality, as quantified by structural similarity metrics.