# Reconfigurable continuous-zoom metalens in visible

## TL;DR

This paper introduces a reconfigurable continuous-zoom metalens using chiral metasurfaces that can vary focal length by rotation and polarization control, offering a compact alternative to traditional zoom lenses.

## Contribution

The design of a polarization-dependent, reconfigurable metalens that enables continuous zoom without mechanical adjustments, utilizing chiral metasurfaces for flexible focal length control.

## Key findings

- Focal length can be continuously tuned from negative to positive infinity.
- The metalens's polarization dependence allows switching between positive and negative focal lengths.
- The design offers a compact, flexible alternative to traditional zoom lenses.

## Abstract

Design of a conventional zoom lens is always challengeable because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for lens adjustment. In this paper, we propose a continuous zoom lens consisting of two chiral geometric metasurfaces with dielectric nanobrick arrays sitting on a transparent substrate. The metalens can continuously vary the focal length by rotating either of the two metasurfaces along its optical axis without changing any other conditions. More importantly, because of the polarization dependence of the geometric metasurface, the positive and negative polarities are interchangeable in one identical metalens only by changing the handedness of the incident circularly polarized light, which can generate varyingfocal lengths ranging from negative infinity to positive infinity in principle. On account of its advantages of compactness, flexibility and easiness in design, the proposed zoom metalens can provide new perspectives for the development of continuous-zoom optical system and it can find applications in fields which require ultracompact and continuous-zoom imaging and reconfigurable beam wavefront steering.

---
Source: https://tomesphere.com/paper/1905.06696