# A Polarization-Multiplexed Multifunctional Metalens for Triple-Focus Coplanar Imaging

## TL;DR

This paper introduces a metalens that can focus three types of polarized light at once, enabling advanced imaging with potential for compact and efficient devices.

## Contribution

The novel metalens design enables triple-polarization imaging through a single aperture using spatially multiplexed meta-atoms.

## Key findings

- The metalens creates three coplanar focal spots with horizontal, vertical, and circular polarization.
- It achieves a total focusing efficiency of 60% under circularly polarized light.
- The device supports real-time triple-polarization imaging for integrated systems.

## Abstract

Metalenses capable of controlling more than two types of polarized light have drawn broad interest recently, as they can bring great flexibility and possibilities to the design of highly integrated polarization imaging devices that are not limited by theoretical efficiency. However, current metalenses for practical applications can only perform imaging with dual-polarization states simultaneously through a single aperture. Herein, a polarization-multiplexed multifunctional metalens enabled with three kinds of phase manipulation is proposed. Specifically, by encoding three groups of specific meta-atoms within a single aperture through spatial multiplexing, a “three-in-one” meta-device acting as a composite metalens can be constructed. Theoretical analysis and calculation simulations validate the performance of the metalens. Under circularly polarized light, the metalens exhibits three nearly diffraction-limited coplanar focal spots with horizontal, vertical, and circular polarization properties, respectively, and has a total focusing efficiency of 60%. This device can be used for triple-polarization imaging in real time, with promising prospects in highly integrated polarization imaging systems.