Mid-infrared high performance dual-Fano resonances based on all-dielectric metasurface for refractive index and gas sensing

• Published in: Optics and laser technology 2024-10, Vol.177, p.111140, Article 111140
• Main Authors: Liu, Zeqian, Wang, Bin, Wang, Shang, Du, Jiansen, Chi, Zongtao, Li, Ning
• Format: Article
• Language: English
• Subjects: All-dielectric metasurface; Gas sensing; High Q-factor; Polarization insensitivity; Refractive index sensing
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2024.111140

•High-Q Dual-Resonance Metasurface: We propose a novel square nanoblock octamer all-dielectric metasurface capable of generating dual-resonance modes with exceptional Q-factors in the mid-infrared spectrum.•Physical Mechanism Analysis: Through multipole decomposition and electromagnetic field distribution analysis, we elucidate the physical mechanisms underlying the dual-resonance modes, which are dominated by toroidal dipole (TD) and magnetic quadrupole (MQ), respectively.•Exceptional Sensing Performance: Our result demonstrates outstanding refractive index sensing performance, achieving a maximum sensitivity of 3666 nm/RIU and a figure of merit (FoM) of 55,302 RIU-1.•Gas Sensing Capabilities: By incorporating gas-sensitive films, our metasurface serves as highly sensitive gas sensors capable of detecting hydrogen and methane with sensitivities of −1.304 nm/% and −0.484 nm/% for hydrogen, and −2.366 nm/% and −8.917 nm/% for methane, respectively.•Significance: Our research contributes to the development of high-performance mid-infrared refractive index, hydrogen, and methane sensor devices, with potential applications in various fields including environmental monitoring, medical diagnostics, and industrial safety. The attainment of dual-resonance boasting high Q-factors in the mid-infrared spectrum stands as a captivating domain of inquiry. In this paper, a square nanoblock octamer all-dielectric metasurface is proposed. It generates dual-band responses in the mid-infrared band, exhibiting exceptional Q-factors of up to 15,149 and 120,856 respectively. The data evince a remarkable alignment between the Q-factor derived from fitting the Fano resonances and that computed through FWHM. Multipole decomposition and electromagnetic field distributions indicate dual-resonance modes are controlled by toroidal dipole (TD) and magnetic dipole (MD). The maximum sensitivity to the refractive index is 3666 nm/RIU, the maximum FoM is 55,302 RIU−1, and the polarization is insensitive. Gas sensors can be developed by filling the metasurface structure with hydrogen and methane-sensitive films. This sensor has a maximum sensitivity of −1.304 nm/% for hydrogen and −8.917 nm/% for methane. This research provides an important and effective approach to achieving high-performance mid-infrared refractive index, hydrogen, and methane sensor devices.