Ultrasensitive Optical Sensing Based on Non-Hermitian Metasurfaces

Mohamed Farhat, Pai-Yen Chen

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We present here an ultrasensitive optical sensing technique based on the parity-time (PT)-symmetric non-Hermitian metasurfaces. The system is composed of a pair of active and passive metasurfaces with the subtle gain-loss balance. Specifically, these two metasurfaces are made of the photoexcited, nanopatterned 2D material (gain) and the lossy metallic structure (i.e., loss). By suitably tailoring the impedance profiles of the PT-symmetric metasurfaces, the system can exhibit an exotic point where the coherent perfect absorption (CPA) and lasing could occur at the same wavelength, switchable via tuning the complex amplitude of incoming light. At this point, tiny perturbation in the effective optical impedance could drastically vary eigenvalues of the scattering matrix, leading to greatly modulated scattering coefficients and output factor, well beyond conventional optical sensors. Our results show that the proposed PTsymmetric metasurfaces may enable ultrasensitive optical sensors for detecting low-density chemical, gas and molecular agents, as well as refractive-index sensing of a nanofilm.
Original languageEnglish (US)
Title of host publicationMicro- and Nanotechnology Sensors, Systems, and Applications XI
ISBN (Print)9781510626294
StatePublished - 2019

Bibliographical note

KAUST Repository Item: Exported on 2021-09-02


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