Resolution enhancement in surface plasmon resonance sensor based on waveguide coupled mode by combining a bimetallic...

Area of Science:

• Optoelectronics
• Nanotechnology
• Chemical Sensing

Background:

• Surface plasmon resonance (SPR) sensors offer high sensitivity but face limitations in resolution.
• Enhancing SPR sensor resolution is crucial for detecting low-concentration analytes and subtle surface changes.

Purpose of the Study:

• To introduce and validate a novel method for significantly enhancing the resolution of SPR sensors.
• To explore the synergistic effects of waveguide coupling and bimetallic nanostructures for improved SPR sensing.

Main Methods:

• Theoretical modeling using Fresnel equations for a multilayer stack (prism/Ag/waveguide/Au).
• Experimental verification of the proposed sensor design using a Zinc Sulfide-Silicon Dioxide (ZnS-SiO2) waveguide layer.
• Coupling incident light to a guided wave using an inner silver (Ag) layer to concentrate fields on the outer gold (Au) surface.

Main Results:

• Demonstrated a substantial enhancement in the resolution of the SPR sensor.
• The combined waveguide-coupled plasmonic mode and Au/Ag bimetallic structure effectively concentrated electromagnetic fields.
• Experimental results validated the theoretical predictions for the enhanced resolution.

Conclusions:

• The proposed approach offers a promising route to overcome resolution limitations in current SPR sensors.
• The integration of waveguide coupling and bimetallic enhancement provides a powerful strategy for next-generation SPR sensor development.
• This work paves the way for more sensitive and precise molecular detection and surface analysis.