Surface plasmon resonance biosensor based on graphene and grating excitation

Area of Science:

• Nanotechnology
• Biosensing
• Optoelectronics

Background:

• Surface plasmon resonance (SPR) biosensors are crucial for detecting biomolecular interactions.
• Graphene's unique properties offer potential for enhancing biosensor performance.
• Grating structures can improve light coupling and enhance SPR excitation.

Purpose of the Study:

• To propose and simulate a novel SPR biosensor utilizing a graphene-decorated grating structure.
• To investigate the sensor's performance in the mid-infrared spectral region.
• To evaluate the sensor's sensitivity and measurement range for analytes.

Main Methods:

• Fabrication of a three-layer sensor structure: graphene, silica grating, and high refractive index layer.
• Excitation of surface plasmons using transverse magnetic polarized light.
• Simulation of sensor properties using the finite-difference time-domain (FDTD) method.

Main Results:

• The proposed sensor design localizes surface plasmons effectively at the graphene layer.
• A high refractive index layer enhances light absorption and spectral depth.
• A linear relationship between analyte refractive index (RI) and resonance wavelength was observed.

Conclusions:

• The graphene-decorated grating SPR biosensor shows promise for sensitive analyte detection.
• The sensor achieved a sensitivity of 2780 nm/RIU over a measurement range of 1-1.8 RI.
• The FDTD simulation method allows for structural optimization to further improve sensor performance.