Engineering mode coupling in a hybrid plasmon-photonic cavity for dual-band infrared spectroscopic gas sensing

Research output: Contribution to journalArticlepeer-review

Abstract

On-chip infrared spectroscopy has become one of the indispensable key technologies
for miniature biochemical sensors, gas sensors, food quality control, and environmental monitoring
systems. The most important requirement for on-chip spectroscopic sensors is to miniaturize
spectroscopic functions to be integrated into thermal emitters and infrared detectors. In this work,
we propose a hybrid plasmon-photonic system consisting of a plasmonic grating coupled to a
distributed Bragg reflector (DBR)-dielectric-metal cavity for on-chip dual-band spectroscopic
sensing applications. The strong coupling between surface-plasmon polaritons and the cavity
resonance leads to the hybridization of the photonic states; the mode splitting, the photonic
band folding, and the formation of new eigenstates including bound states in the continuum are
observed in the system. It is shown that, by engineering the photonic coupling, a dual-band
resonant near-perfect absorber is achievable and easily controllable. As a proof of concept, we
numerically demonstrate a set of five different dual-band absorbers for CO2, N2O, CO, NO, and
NO2 gas sensing applications. The dual-band absorbers can be used for on-chip spectroscopic
thermal emitters or infrared detectors in gas sensors. The hybrid plasmon-photonic system can
be an attractive photonic platform for applications in emitting and sensing photonic devices
Original languageEnglish
Pages (from-to)1827
JournalOSA Continuum
Volume4
Issue number6
DOIs
Publication statusPublished - 15 Jun 2021

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