Improved Refractive Index-Sensing Performance of Multimode Fano-Resonance-Based Metal-Insulator-Metal Nanostructures

Abstract

This work proposed a multiple mode Fano resonance-based refractive index sensor with high sensitivity that is a rarely investigated structure. The designed device consists of a metal–insulator–metal (MIM) waveguide with two rectangular stubs side-coupled with an elliptical resonator embedded with an air path in the resonator and several metal defects set in the bus waveguide. We systematically studied three types of sensor structures employing the finite element method. Results show that the surface plasmon mode’s splitting is affected by the geometry of the sensor. We found that the transmittance dips and peaks can dramatically change by adding the dual air stubs, and the light–matter interaction can effectively enhance by embedding an air path in the resonator and the metal defects in the bus waveguide. The double air stubs and an air path contribute to the cavity plasmon resonance, and the metal defects facilitate the gap plasmon resonance in the proposed plasmonic sensor, resulting in remarkable characteristics compared with those of plasmonic sensors. The high sensitivity of 2600 nm/RIU and 1200 nm/RIU can simultaneously achieve in mode 1 and mode 2 of the proposed type 3 structure, which considerably raises the sensitivity by 216.67% for mode 1 and 133.33% for mode 2 compared to its regular counterpart, i.e., type 2 structure. The designed sensing structure can detect the material’s refractive index in a wide range of gas, liquids, and biomaterials (e.g., hemoglobin concentration).

An Efficient Photonic Crystal‐Based Chemical Sensor for the Detection of Isopropanol, Ethanol, and Acetone

“…Examples of these methods include the finite element (FiE), the plane-wave expansion (PWEN), and the finite-difference time domain (FDTDN). [40,41] For a 1D PHC, a variety of numerical techniques, including FDTDN [42] and FiE, [43] can be used to model the transmission spectrum. To examine the optical characteristics of 1D PHC, the TrMx approach offers a straightforward and adaptable method.…”

Research on Fano Resonance Sensing Characteristics Based on Racetrack Resonant Cavity

“…The m = 1 mode corresponds to a weakening Fano resonance peak. This is attributed to the change in R affecting the change in the narrowband mode, where this corresponding change in the narrowband mode leads to changes in the position and transmittance of the Fano resonance [33]. The change in the Fano resonance peak with the refractive index △n under the symmetry mode m = 1 is shown in Figure 5b.…”

All-Dielectric Refractive Index Sensor Based on Multiple Fano Resonance with High Sensitivity in the Long-Wave Infrared Region

“…At present, the research interest of Fano resonance has shifted from single Fano resonance to multiple Fano resonance because of the different applications. Multiple Fano resonance [19][20][21][22][23] can be widely used in multi wavelength surface enhanced spectroscopy, multi-band slow light devices and multi-channel biosensors. For example, a multiple Fano resonance all-dielectric devices for RI sensing was proposed by Su et al [24] whose the maximum S is 392 nm/RIU.…”