Engineering multimodal dielectric resonance of TiO2 based nanostructures for high-performance refractive index sensing applications

Muhammad Aamir Abbas, Amna Zubair, Kashif Riaz, Wei Huang, Jinghua Teng, Muhammad Qasim Mehmood, Muhammad Zubair

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Optical metasurface based refractive index (RI) sensors find applications in chemical, environmental, biomedical, and food processing industries. The existing RI sensors based on metals suffer from the plasmonic loss in the optical regime; in contrast, those based on Fano-type resonances generated by dielectric materials are either polarization-sensitive or are based on complex geometrical structures prone to fabrication imperfections that can lead to severe performance degradation. Here, we demonstrate that careful engineering of resonance modes in dielectric metasurfaces based on simple symmetric meta-atoms can overcome these limitations. More specifically, we have designed low-loss high-performance RI sensors using all-dielectric metasurfaces composed of TiO2 based nanostructures of three different shapes (i.e., cylindrical, square and elliptical) operating at near-infrared (NIR) wavelengths, which are robust against the perturbations of geometric parameters. In terms of physics, this work reports sensor structures achieving sharp resonant dips of high Q-factor in the transmission spectra corresponding to multiple dielectric resonance modes (i.e., electric quadrupole, magnetic dipole, and electric dipole) with superior performance as compared to the state-of-the-art. Four absolute liquids (water, ethanol, pentanol, and carbon tetrachloride) with a refractive index ranging from 1.333 to 1.453 are used to numerically validate the performance, and a maximum sensitivity of 798 nm/RIU with FOM up to 732 has been achieved.
Original languageEnglish (US)
Pages (from-to)23509-23522
Number of pages14
JournalOptics Express
Issue number16
StatePublished - Aug 3 2020
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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