Plasmon-exciton coupling for nanophotonic sensing on chip

Area of Science:

• Materials Science
• Spectroscopy
• Nanotechnology

Background:

• Graphene exhibits unique optical properties beneficial for surface-enhanced Raman scattering (SERS).
• Noble metallic nanostructures are crucial for enhancing Raman signals through plasmonic effects.
• Hybrid systems combining graphene and plasmonic nanoparticles offer synergistic enhancements.

Purpose of the Study:

• To design and fabricate a graphene-noble metallic nanostructure hybrid system for SERS.
• To investigate the Raman enhancement effects of different hybrid configurations.
• To achieve highly sensitive SERS detection using the developed hybrid structure.

Main Methods:

• Fabrication of a sandwich hybrid structure using a Blu-ray disc substrate, silver film, single-layer graphene, and gold nanoparticles (AuNPs).
• Characterization of the hybrid structure's optical properties and Raman enhancement capabilities.
• Evaluation of SERS performance using Rhodamine 6G as a target analyte.

Main Results:

• The Ag grating/graphene/AuNPs sandwich structure achieved a Raman enhancement factor (EF) of 6.2×10⁸.
• A SERS detection limit of 0.1 nM was obtained for Rhodamine 6G.
• Different graphene and AuNP arrangements on the Blu-ray grating showed varying Raman responses.

Conclusions:

• The hybrid structure's enhanced performance is attributed to combined electric field enhancement and graphene's chemical enhancement.
• This study provides a new strategy for SERS detection.
• The developed graphene-plasmon hybrid structures offer a promising technique for designing advanced SERS sensors.