Computational inverse design for ultra-compact single-piece metalenses free of chromatic and angular aberration

We present full-Maxwell topology-optimization design of a single-piece multilayer metalens, about 10 wavelengths lambda in thickness, which simultaneously focuses over a 60 degrees angular range and a 23% spectral bandwidth without suffering chromatic or angular aberration, a plan-achromat. At all angles and frequencies, it achieves diffraction-limited focusing (Strehl ratio>0.8) and an absolute focusing efficiency of >50%. Both 2D and 3D axisymmetric designs are presented, optimized over similar to 10 5 degrees of freedom. We also demonstrate shortening the lens-to-sensor distance while producing the same image as for a longer virtual focal length and maintaining plan-achromaticity. These proof-of-concept designs demonstrate the ultra-compact multifunctionality that can be achieved by exploiting the full wave physics of subwavelength designs and motivate future work on design and fabrication of multilayer metaoptics.

Automated summary

This study presents a full-Maxwell topology-optimized design of a single-piece multilayer metalens that can simultaneously focus within a 60-degree angular range and a 23% spectral bandwidth without suffering chromatic or angular aberration. The design achieves diffraction-limited focusing and an absolute focusing efficiency of over 50% at all angles and frequencies, demonstrating ultra-compact multifunctionality. This paves the way for future work on design and fabrication of multilayer metaoptics.