Chiral phase-imaging meta-sensors

TL;DR

This paper introduces compact, multifunctional photodetectors using chiral plasmonic metasurfaces that can separately measure phase gradients of circular polarization components, enabling advanced imaging and sensing applications.

Contribution

The work presents novel integrated metasurface-based photodetectors capable of selective phase gradient measurement for circular polarization components, offering a compact alternative to bulky traditional systems.

Findings

Achieved an order-of-magnitude polarization selectivity with respect to phase gradient.

Demonstrated simultaneous mapping of right and left circularly-polarized wavefronts.

Proposed a simple imaging setup utilizing these detectors for enhanced polarization imaging.

Abstract

Light waves possess multiple degrees of freedom besides intensity, including phase and polarization, that often contain important information but require complex and bulky systems for their measurement. Here we report a pair of compact multifunctional photodetectors that can selectively measure the local phase gradient of, respectively, the right and left circular-polarization component of any incident wave. These devices employ a chiral pair of integrated plasmonic metasurfaces to introduce a sharp dependence of responsivity on local direction of propagation of the desired polarization component. An order-of-magnitude polarization selectivity with respect to phase gradient is demonstrated with both devices. Using the measured device characteristics, we also describe computationally a pixel array that allows for the simultaneous separate mapping of the right and left circularly-polarized incident wavefronts in a particularly simple imaging setup. These unique capabilities may be exploited to enable new functionalities for applications in chemical sensing, biomedical microscopy, and machine vision.