Ultrastrong plasmon–phonon coupling via epsilon-near-zero nanocavities

Daehan Yoo, Fernando de León-Pérez, Matthew Pelton, In Ho Lee, Daniel A. Mohr, Markus B. Raschke, Joshua D. Caldwell, Luis Martín-Moreno, Sang Hyun Oh

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82 Scopus citations


Vibrational ultrastrong coupling, where the light–matter coupling strength is comparable to the vibrational frequency of molecules, presents new opportunities to probe the interactions between molecules and zero-point fluctuations, harness cavity-modified chemical reactions and develop novel devices in the mid-infrared spectral range. Here we use epsilon-near-zero nanocavities filled with a model polar medium (SiO2) to demonstrate ultrastrong coupling between phonons and gap plasmons. We present classical and quantum-mechanical models to quantitatively describe the observed plasmon–phonon ultrastrong coupling phenomena and demonstrate a modal splitting of up to 50% of the resonant frequency (normalized coupling strength η > 0.25). Our wafer-scale nanocavity platform will enable a broad range of vibrational transitions to be harnessed for ultrastrong coupling applications.

Original languageEnglish (US)
Pages (from-to)125-130
Number of pages6
JournalNature Photonics
Issue number2
StatePublished - Feb 2021

Bibliographical note

Funding Information:
We thank T. W. Ebbesen for helpful comments. This research was supported by grants from the US National Science Foundation (ECCS 1809240 to D.Y., D.A.M., S.-H.O.; ECCS 1809723 to I.-H.L., S.-H.O.) and the Samsung Global Research Outreach (GRO) Program (to S.-H.O.). F.d.L.-P. and L.M.-M. acknowledge financial support from the Spanish Ministry of Economy and Competitivity through projects MAT2017-88358-C3-1-R and MAT2017-88358-C3-2-R and the Aragón Government project Q-MAD. M.P. acknowledges support from the US National Science Foundation (NSF DMR-1905135). M.B.R. acknowledges funding from the US National Science Foundation (NSF CHE-1709822). J.D.C. was supported by the Office of Naval Research Grant N00014-18-12107. S.-H.O. further acknowledges support from the Sanford P. Bordeau Chair in Electrical Engineering at the University of Minnesota.

Publisher Copyright:
© 2020, The Author(s), under exclusive licence to Springer Nature Limited.


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