Symmetry breaking of Pancharatnam-Berry phase using non-axisymmetric meta-atoms

TL;DR

This paper introduces a method to break the symmetry restriction of the Pancharatnam-Berry phase in metasurfaces by using non-axisymmetric meta-atoms, enabling advanced wavefront control and holography.

Contribution

It reveals a general mechanism to break PB-phase symmetry restriction through asymmetric meta-atoms and demonstrates a QR-code structured meta-atom for polarization multiplexing holography.

Findings

Successfully demonstrated circular-polarization multiplexing holography

Designed a novel QR-code structured meta-atom

Provided new understanding of PB phase manipulation

Abstract

The Pancharatnam-Berry (PB) phase in metasurfaces obeys the symmetry restriction, according to which the PB phases of two orthogonal circularly polarized waves are the same but with opposite signs. Here, we reveal a general mechanism to break the axisymmetry of meta-atoms in order to break the PB-phase symmetry restriction. As a proof of concept, we designed a novel meta-atom with a QR-code structure and successfully demonstrated circular-polarization multiplexing metasurface holography. This study provides a fundamentally new understanding of the PB phase and opens a path for arbitrary wavefront engineering using asymmetric electromagnetic structures.