Strong coupling between quasi-bound states in the continuum and molecular vibrations in the mid-infrared

Kaili Sun, Min Sun, Yangjian Cai, Uriel Levy, Zhanghua Han*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Strong light-matter coupling is of much interest for both fundamental research and technological applications. The recently studied bound state in the continuum (BIC) phenomenon in photonics with controlled radiation loss rate significantly facilitates the realization of the strong coupling effect. In this work, we report the experimental observation of room temperature strong coupling between quasi-BIC resonances supported by a zigzag metasurface array of germanium elliptical disks and the vibrational resonance of polymethyl methacrylate (PMMA) molecules in the mid-infrared. Based on the approach of tuning the quasi-BIC resonance by changing the thickness of the coated PMMA layer, we can easily observe the strong coupling phenomenon, manifested by significant spectral splitting and typical anti-crossing behaviors in the transmission spectrum, with the spectral distance between the two hybrid photon-vibration resonances significantly larger than the bandwidth of both the quasi-BIC resonance and the PMMA absorption line. Our results demonstrate that the use of quasi-BIC resonance in all-dielectric nanostructures provides an effective and convenient approach for the realization of strong coupling effect.

Original languageAmerican English
Pages (from-to)4221-4229
Number of pages9
Issue number18
StatePublished - 3 Sep 2022

Bibliographical note

Funding Information:
Research funding: This work was supported by the national natural science foundation of China under the project number of 11974221.

Publisher Copyright:
© 2022 the author(s), published by De Gruyter, Berlin/Boston.


  • bound state in the continuum
  • strong coupling
  • vibrational resonance


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