Highly tunable elastic dielectric metasurface lenses

TLDR

Dielectric metasurfaces are two‑dimensional arrays of nano‑scatterers that control optical phase and polarization with subwavelength resolution, enabling ultra‑thin free‑space components, yet most high‑performance devices have fixed parameters. The authors aim to create highly tunable dielectric metasurface devices using silicon nano‑posts embedded in a thin elastic polymer. They fabricate subwavelength‑thick silicon nano‑posts encapsulated in a transparent elastic polymer, allowing mechanical strain to modulate the optical response. A 915‑nm microlens demonstrates focal distance tuning from 600 µm to 1400 µm (952 diopters change) via radial strain while preserving diffraction‑limited focus and over 50 % efficiency, highlighting the concept’s versatility for ultra‑slim, multi‑functional applications. An illustrative image accompanies the publication.

Abstract

Abstract Dielectric metasurfaces are two‐dimensional structures composed of nano‐scatterers that manipulate the phase and polarization of optical waves with subwavelength spatial resolution, thus enabling ultra‐thin components for free‐space optics. While high performance devices with various functionalities, including some that are difficult to achieve using conventional optical setups have been shown, most demonstrated components have fixed parameters. Here, we demonstrate highly tunable dielectric metasurface devices based on subwavelength thick silicon nano‐posts encapsulated in a thin transparent elastic polymer. As proof of concept, we demonstrate a metasurface microlens operating at 915 nm, with focal distance tuning from 600 μm to 1400 μm (over 952 diopters change in optical power) through radial strain, while maintaining a diffraction limited focus and a focusing efficiency above 50%. The demonstrated tunable metasurface concept is highly versatile for developing ultra‐slim, multi‐functional and tunable optical devices with widespread applications ranging from consumer electronics to medical devices and optical communications. image