MIM waveguide structure consisting of a baffle and a ring cavity embedded in a square metal layer

Area of Science:

• Photonics
• Plasmonics
• Nanotechnology

Background:

• Plasmon refractive index nanosensors are crucial for detecting changes in the surrounding environment.
• Fano resonance offers sharp spectral features ideal for sensitive detection.

Purpose of the Study:

• To design and simulate a tunable plasmon refractive index nanosensor based on Fano resonance.
• To investigate the influence of structural parameters on sensor performance.
• To achieve high sensitivity and figure of merit for refractive index sensing.

Main Methods:

• Finite Element Method (FEM) simulations in 2D.
• Design of a metal-insulator-metal waveguide with a silver baffle and a ring cavity in a square (RCSQ).
• Analysis of transmission spectra and electric field distributions.

Main Results:

• Excitation of dual Fano resonances through the proposed structure.
• Demonstration of tunable Fano resonance by adjusting cavity parameters and refractive indices.
• Achieved sensitivity of 2750 nm/RIU and a figure of merit (FOM) of 3.48×10⁴.

Conclusions:

• The proposed RCSQ structure effectively generates tunable Fano resonances for sensing.
• The nanosensor exhibits high sensitivity and FOM, suitable for optical sensing applications.
• This design shows significant potential for advanced optical nanosensor development.