Chirality tuning and reversing with resonant phase-change metasurfaces

TL;DR

This paper presents a method to dynamically control and reverse the chiral response of resonant metasurfaces using phase-change materials, enabling rapid and continuous tuning of circular dichroism for advanced photonic applications.

Contribution

It introduces a novel approach combining phase-change materials with resonant metasurfaces to achieve reversible and tunable chiral responses, overcoming limitations of static and weak modulation.

Findings

Chiral response can be rapidly tuned from -0.947 to +0.958.

Phase transition enables control over chirality sign and magnitude.

Demonstrates potential for advanced chiral photonic devices.

Abstract

Dynamic control of circular dichroism in photonic structures is critically important for compact spectrometers, stereoscopic displays, and information processing exploiting multiple degrees of freedom. Metasurfaces can help miniaturize chiral devices but only produce static and limited chiral responses. While external stimuli are able to tune resonances, their modulations are often weak, and reversing continuously the sign of circular dichroism is extremely challenging. Here, we demonstrate dynamically tunable chiral response of resonant metasurfaces supporting chiral bound states in the continuum combining them with phase-change materials. Phase transition between amorphous and crystalline phases allows to control chiral response and vary chirality rapidly from -0.947 to +0.958 backward and forward via chirality continuum. Our demonstrations underpin the rapid development of chiral photonics and its applications.