Tunable quasi-bound states in the continuum with intrinsic chirality in a phase-change metasurface
Year: 2025
Type: article
Abstract: The realization of switchable high- Q factors with intrinsic chirality is of paramount importance for various applications involving active and nonlinear metadevices that exhibit chiral responses. Here, we present a chiral metasurface that employs amorphous phase-change material, which enables the formation of quasi-bound states in the continuum characterized by inherent optical chirality. By simultaneously breaking both in-plane and out-of-plane symmetries, the metasurface supports multiple high- Q resonances that produce pronounced circular dichroism responses. Through eigenmode simulations and multipolar decomposition analysis, we demonstrate that the quasi-bound states in the continuum originate from various multipolar contributions. These modes are distinguished by sharp spectral features and circular dichroism values nearing unity, indicating near-perfect polarization selectivity. Furthermore, we illustrate that the intrinsic chirality and high- Q response can be actively deactivated by inducing the phase transition in the Ge 2 Sb 2 Te 5 material to its crystalline state, which leads to significant optical losses and the suppression of the quasi-bound states in the continuum. Our findings establish a versatile and tunable photonic platform for dynamically reconfigurable chiroptical devices, offering promising prospects for applications in optical communication, biosensing, and quantum photonics.
Source: Optics Express
DOI: 10.1364/oe.566464
Authors: Jianhua Zeng, Yu Zhou, Xiang Fu, Jianrong Yang, Yuxin Chen, Weiyi Hong
Institutions: Shangrao Normal University, South China Normal University
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,270
Awards: G1989298081, G5241879143
OpenAlex ID: W4411131678