Centimeter-Scale Achromatic Hybrid Metalens Design: A New Paradigm Based on Differentiable Ray Tracing in the Visible Spectrum

TL;DR

This paper introduces a novel hybrid metalens design using differentiable ray tracing, enabling achromatic performance across the visible spectrum for large apertures, advancing optical and computational imaging applications.

Contribution

It presents a new paradigm for hybrid metalens design based on differentiable ray tracing, allowing joint optimization for broadband achromatic performance.

Findings

Achieves achromatic performance from 440-700 nm spectrum.

Supports large aperture of 1 cm with f/1.4.

Seamless integration into differentiable imaging systems.

Abstract

Single metalenses are limited by their physical constraints, precluding themselves from achieving high numerical aperture across a wide visible spectral band in large-aperture applications. A hybrid system that integrates a metalens with a refractive lens can address this issue, yet previous designs lacked sufficient flexibility. Here, by reanalyzing the generalized Snell's law, we introduce a new paradigm for the hybrid metalens design based on differentiable ray tracing. Through joint optimization of the phase distribution of the metalens and refractive lens parameters, our system achieves achromatic performance within the broad spectral range of 440-700 nm, with an aperture of 1 cm and an f-number of 1.4. Owing to the differentiable nature of the proposed system, it can be seamlessly integrated as the optical front-end into any differentiable computational imaging system. Our system offers unprecedented opportunities for the advancement of metalenses in innovative optical design and computational imaging domains.