Tunable coupling between molecular vibration and sub-radiant magnetic quadrupole in a plasmonic metasurface

Qiqige Wulan; Jiachen Yu; Li Xing; Zhijun Liu

doi:10.1117/12.2686759

22 December 2023 Tunable coupling between molecular vibration and sub-radiant magnetic quadrupole in a plasmonic metasurface

Qiqige Wulan, Jiachen Yu, Li Xing, Zhijun Liu

Author Affiliations +

Proceedings Volume 12773, Nanophotonics and Micro/Nano Optics IX; 1277309 (2023) https://doi.org/10.1117/12.2686759
Event: SPIE/COS Photonics Asia, 2023, Beijing, China

Abstract

Strong coupling between plasmonic resonances in metallic nanostructures and molecule vibrations has been reported in structures such as metallic dimers and nanoparticles on mirror, forming new hybrid states called ‘plexcitons’. Strong coupling occurs when the energy exchange rate exceeds the damping rates of both optical mode and the molecular vibration. Sub-radiant plasmonic modes with high quality factor have often been considered as promising candidates for achieving strong coupling with molecules. However, the sub-radiant plasmon mode cannot be directly excited by farfield normal incident plane wave due to destructive interaction among the moments with equal magnitudes but opposite directions, completely cancelling each other out. In this work, we demonstrate a plasmonic metasurface, which exhibits a sub-radiant magnetic quadrupole (MQ) resonance and tunable coupling strength with molecular vibrations. Our fabricated metasurface consists of an asymmetric metallic micro-cross array on top of a dielectric spacer backed with a metallic film. A magnetic quadrupole resonance is excited at 37.8THz at far-field normal incidence condition. Its quality factor reaches 34, which is more than four times of regular radiant magnetic dipole excited in the same structure. Coupling of the MQ resonance with vibration band (Si-CH₃ at 37.8THz) of polydimethylsiloxane (PDMS) leads to Rabi splitting phenomenon in the dispersion curve. As thickness of the spin-coated PDMS film increases from 14 nm to 310 nm, the Rabi splitting gap increases from 0.6THz to 1.13THz, exhibiting a tunable coupling strength. Our demonstrated magnetic quadrupole metasurface presents a versatile scheme for manipulating the light-matter interaction in sensing application.

(2023) Published by SPIE. Downloading of the abstract is permitted for personal use only.

Citation Download Citation

Qiqige Wulan, Jiachen Yu, Li Xing, and Zhijun Liu "Tunable coupling between molecular vibration and sub-radiant magnetic quadrupole in a plasmonic metasurface", Proc. SPIE 12773, Nanophotonics and Micro/Nano Optics IX, 1277309 (22 December 2023); https://doi.org/10.1117/12.2686759

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
4 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Magnetism

Vibration

Plasmonics

Molecules

Mirrors

Molecular interactions

Nanoparticles

Show All Keywords

Keywords/Phrases

Search In:

Publication Years