Fano resonance based on D-shaped waveguide structure and its application for human hemoglobin detection

Area of Science:

• Photonics and Nanophotonics
• Plasmonics
• Sensing Technologies

Background:

• Fano resonance is a key phenomenon in photonics, enabling applications like high-sensitivity sensing and electromagnetic-induced transparency.
• Metal-insulator-metal (MIM) waveguide structures offer a versatile platform for manipulating light at the nanoscale.

Purpose of the Study:

• To propose and analyze a novel MIM waveguide structure for achieving Fano resonance.
• To investigate the tunability of Fano resonance by altering geometric parameters and refractive index.
• To demonstrate the potential of the structure for high-sensitivity biosensing applications.

Main Methods:

• Utilized the finite element method (FEM) for detailed analysis of transmission characteristics and magnetic-field distributions.
• Designed a MIM waveguide structure with a D-shaped cavity and a silver-air-silver barrier.
• Simulated Fano resonance and its dependence on structural and environmental parameters.

Main Results:

• Achieved Fano resonance through the interaction between the D-shaped cavity and the bus waveguide.
• Demonstrated tunability of Fano resonance by adjusting geometric parameters and the refractive index of the D-shaped cavity.
• Obtained a maximum refractive index sensitivity of 1510 nm/RIU with a linear relationship between resonance wavelength and refractive index.

Conclusions:

• The proposed MIM waveguide structure effectively exhibits tunable Fano resonance.
• The structure shows high sensitivity and linearity, making it suitable for refractive index sensing.
• The study highlights the potential of this plasmonic sensor for bio-sensing, including human hemoglobin and blood group detection.