Enhanced sensor based on Fano resonance in a Al2O3/Ag hybrid metamaterial

• Published in: Optical and quantum electronics 2024-10, Vol.56 (10), Article 1666
• Main Authors: Li, Yuchang, Chen, Fang, Gao, Wankun, Yang, Wenxing
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Characterization and Evaluation of Materials; Computer Communication Networks; Concentric cylinders; Coupled modes; Electrical Engineering; Fano resonance; Figure of merit; Finite difference time domain method; Hybrid structures; Lasers; Line shape; Metamaterials; Optical Devices; Optics; Parameter sensitivity; Photonics; Physics; Physics and Astronomy; Polaritons; Silver; Surface plasmon resonance
• ISSN: 1572-817X; 0306-8919; 1572-817X
• DOI: 10.1007/s11082-024-07613-y

In this paper, we design a Fano resonance sensor based on Al 2 O 3 and Ag hybrid metamaterial, the proposed hybrid structure is composed of two concentric cylinders with the same radius. Finite difference time domain (FDTD) simulation and coupled mode theory (CMT) are used to study the transmission characteristics of the structure. The results indicate that the Fano resonance in this structure is caused by the destructive interaction between the surface plasmon polaritons (SPPs) generated at the interface of Al 2 O 3 /Ag and the local surface plasmon resonances (LSPRs) excited at the Ag boundary. The resonance wavelength and line shape of the Fano resonance can be adjusted by the structural geometrical parameters. Additionally, we incorporate four silver bars into the proposed structure to induce a dual Fano resonance, and the dual Fano resonances can be tuned by the size and position of the silver bars. After optimizing the geometric parameters, the maximum sensitivity of the single Fano resonance structure is S = 119 nm/RIU , and its figure of merit is F O M = 63 . 4 RIU - 1 . The maximum sensitivity of the dual Fano resonance configuration is S = 407 . 8 nm/RIU , which is more than three times as sensitive in the Ag/Al 2 O 3 hybrid metamaterial without the four silver bars, while its figure of merit is F O M = 203 . 7 RIU - 1 . The Fano resonance effect has potential applications in various nanophotonic devices, such as switches, sensors, and modulators.