Inverse-Designed Stretchable Metalens with Tunable Focal Distance

TL;DR

This paper introduces an inverse-designed, stretchable millimeter wave metalens that can be tuned over a fourfold focal distance range, fabricated via 3D printing, with high efficiency and near-diffraction-limited focusing.

Contribution

It presents a novel inverse-design approach for creating a stretchable, all-dielectric metalens with tunable focus, outperforming traditional lenses in material efficiency and tunability.

Findings

Focal distance can be tuned by a factor of 4 with 75% stretch.

Achieves nearly diffraction-limited focal spot.

Focusing efficiency is approximately 70%.

Abstract

In this paper we present an inverse-designed 3D-printed all-dielectric stretchable millimeter wave metalens with a tunable focal distance. Computational inverse-design method is used to design a flat metalens made of disconnected building polymer blocks with complex shapes, as opposed to conventional monolithic lenses. Proposed metalens provides better performance than a conventional Fresnel lens, using lesser amount of material and enabling larger focal distance tunability. The metalens is fabricated using a commercial 3D-printer and attached to a stretchable platform. Measurements and simulations show that focal distance can be tuned by a factor of 4 with a stretching factor of only 75%, a nearly diffraction-limited focal spot, and with a 70% focusing efficiency. The proposed platform can be extended for design and fabrication of multiple electromagnetic devices working from visible to microwave radiation depending on scaling of the devices.