Decoupled phase modulation for circularly polarized lights via chiral metasurface

TL;DR

This paper introduces a novel chiral metasurface design that achieves fully decoupled phase modulation of circularly polarized light, overcoming previous limitations of interrelated spin-state modulation methods.

Contribution

The study presents a new phase modulation pathway using chiral V-shaped holes, enabling independent control of each eigen spin-state in metasurfaces.

Findings

Demonstrated decoupled phase modulation experimentally and numerically.

Achieved independent manipulation of left- and right-handed circular polarization phases.

Expanded phase engineering capabilities in metasurfaces.

Abstract

Metasurfaces are believed as one of the best candidates in nano-optical devices, attributed to the key feasible modulation features of phase, polarization, and local field enhancement by structural designing. However, current methods of propagation- and geometric-phase modulation are interrelated between two eigen spin-states. This means that when the left-handed component phase of a beam is modulated by metasurfaces, its right-handed component phase will change accordingly, which limits the versatility of spin-decoupled applications. In this paper, we experimentally and numerically demonstrate a new phase modulation pathway based on chiral V-shaped holes, which enable fully decoupled one-handed phase modulation of the two eigen spin-states. Two enantiomers are proposed to realize decoupled functions for the two eign-states, e.g., the enantiomer can manipulate the left-handed component phase of a laser beam without changes of the right-handed component. This proposed method has significant meaning in metasurfaces, which can expand the methods of phase engineering.