Double-lobe coupled system induced Fano resonances for high sensitivity plasmonic nanosensors

High sensitivity sensor is of great significance in chemical and biological detection. Here, a high-performance plasmonic sensor based on a double-lobe cavity and rectangular-arc cavity structure is investigated by finite element method. Simulation results show that two independently tunable Fano resonances and one Lorentzian peak can be observed in the transmission spectrum, which can be flexibly regulated by adjusting the structural parameters. In addition, the second Fano peak can be adjusted by applying external pressure. These characteristics make our system convenient for use in high sensitivity refractive index and optical pressure sensors with a maximum sensitivity of 2900 nm/RIU and 4.91 nm/MPa and can be enhanced up to 4200 nm/RIU and 29.28 nm/MPa, respectively, due to the gap plasmon excitation by adding a metal baffle. Our results demonstrate that this novel structure exhibits superior sensing performance, which can offer valuable insights for future advancements in the fields of integrated photonics devices and nano-sensors.