Hybrid Metal-Dielectric Metasurfaces for Refractive Index Sensing

Debdatta Ray, T.V. Raziman, Christian Santschi, Dordaneh Etezadi, Hatice Altug, Olivier J F Martin (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

42 Citations (Scopus)


Hybrid metal-dielectric nanostructures have recently gained prominence because they combine strong field enhancement of plasmonic metals and the several low-loss radiation channels of dielectric resonators, which are qualities pertaining to the best of both worlds. In this work, an array of such hybrid nanoantennas is successfully fabricated over a large area and utilized for bulk refractive index sensing with a sensitivity of 208 nm/RIU. Each nanoantenna combines a Si cylinder with an Al disk, separated by a SiO2 spacer. Its optical response is analyzed in detail using the multipoles supported by its subparts and their mutual coupling. The nanoantenna is further modified experimentally with an undercut in the SiO2 region to increase the interaction of the electric field with the background medium, which augments the sensitivity to 245 nm/RIU. A detailed multipole analysis of the hybrid nanoantenna supports our experimental findings.

Original languageEnglish
Pages (from-to)8752-8759
Number of pages8
JournalNano Letters
Issue number12
Early online date18 Nov 2020
Publication statusPublished - 9 Dec 2020


FundersFunder number
Swiss Government Excellence Scholarship
Horizon 2020 Framework Programme682167, 695206, 777714
European Research Council
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung200021_162453


    • bulk refractive index sensing
    • Hybrid nanoantenna
    • hybridization
    • LSPR
    • undercut


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