Adaptive metalenses with simultaneous electrical control of focal length, astigmatism, and shift

TLDR

Focal adjustment and zooming are universal features of cameras and advanced optical systems, typically achieved by longitudinal mechanical or electrical control of focal length. The study aims to develop electrically tunable large‑area metalenses that, unlike conventional longitudinal tuning, use lateral motion via artificial muscles to achieve >100 % focal length adjustment and simultaneous astigmatism and image shift corrections. The metalens uses strain fields induced by artificial muscles to map onto the optical wavefront, enabling large diffraction‑limited focal length tuning and simultaneous control of astigmatism and image shift. The 30 µm‑thick device demonstrates >100 % focal length tuning, on‑the‑fly astigmatism and image shift correction, and suggests the feasibility of fully electronic optical microscopes and compact adaptive‑optics systems correcting multiple aberrations.

Abstract

Focal adjustment and zooming are universal features of cameras and advanced optical systems. Such tuning is usually performed longitudinally along the optical axis by mechanical or electrical control of focal length. However, the recent advent of ultrathin planar lenses based on metasurfaces (metalenses), which opens the door to future drastic miniaturization of mobile devices such as cell phones and wearable displays, mandates fundamentally different forms of tuning based on lateral motion rather than longitudinal motion. Theory shows that the strain field of a metalens substrate can be directly mapped into the outgoing optical wavefront to achieve large diffraction-limited focal length tuning and control of aberrations. We demonstrate electrically tunable large-area metalenses controlled by artificial muscles capable of simultaneously performing focal length tuning (>100%) as well as on-the-fly astigmatism and image shift corrections, which until now were only possible in electron optics. The device thickness is only 30 μm. Our results demonstrate the possibility of future optical microscopes that fully operate electronically, as well as compact optical systems that use the principles of adaptive optics to correct many orders of aberrations simultaneously.