Abstract
Chiral optical meta surfaces have emerged as a promising platform in coupling with molecular vibrational fingerprints through the enhanced light-matter interaction under different circularly polarized light illumination. This work reports the mode coupling between the mid-infrared phonon vibrations of polymethyl methacrylate (PMMA) molecules, and the thermally tunable chiral meta surfaces based on the phase-change material Ge₂Sb₂Te₅ (GST-225). Phase-change chiral meta surfaces with high circular dichroism (CD) in absorption and tunable plasmonic resonance in the frequency range of 48-56 THz are demonstrated, which covers the phonon vibrational frequency of PMMA molecules at 52 THz. The mode splitting features are observed in the absorption and CD spectra when the meta surface resonance is tuned across the phonon vibrational frequency of PMMA molecules during the phase transition of GST-225. The underlying mechanism of molecule-meta surface coupling is further revealed by studying the electric field and power loss density distributions of the phonon-plasmon coupled modes under both left-handed and right-handed circularly polarized (LCP and RCP) light. The demonstrated results show the potential of dynamically tunable chiral meta surfaces for the applications in label-free molecular sensing, biomedical diagnostics, thermal imaging, and mid-infrared photonics.
Recommended Citation
H. Tang et al., "Tunable Phase-change Metasurfaces Coupled with Mid-infrared Molecular Vibrations," Nanotechnology, vol. 36, no. 50, IOP Publishing, Dec 2025.
The definitive version is available at https://doi.org/10.1088/1361-6528/ae2514
Department(s)
Mechanical and Aerospace Engineering
Keywords and Phrases
chiral metasurface; molecule-metasurface coupling; phase-change metasurface
International Standard Serial Number (ISSN)
1361-6528
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2025 IOP Publishing, All rights reserved.
Publication Date
09 Dec 2025
PubMed ID
41308202
