Enhancing the sensitivity of a transmissive graphene-based plasmonic biosensor

Area of Science:

• Plasmonics
• Terahertz (THz) biosensing
• Graphene-based nanodevices

Background:

• Terahertz (THz) biosensors offer label-free detection of biomolecules.
• Graphene's unique properties can enhance THz wave interactions.
• Improving sensitivity in THz biosensing remains a key challenge.

Purpose of the Study:

• To design and investigate a novel graphene-based biosensor platform operating in the terahertz range.
• To enhance the sensitivity of a THz biosensor through structural modifications.
• To explore the impact of graphene layering and substrate material on biosensor performance.

Main Methods:

• Development of a nanofluidic channel biosensor with a graphene patch and grounded graphene layers.
• Simulation and analysis of scattering parameters to detect molecular presence.
• Systematic variation of graphene sheet numbers and substrate materials (Silicon, Silica).
• Investigation of sensor response to changes in the refractive index of the sensing layer.

Main Results:

• Increasing the number of graphene sheets significantly enhances absorption and sensitivity.
• A maximum sensitivity of 8470 nm/RIU was achieved by inserting a graphene sheet between two others.
• Further sensitivity enhancement to 15410 nm/RIU was observed when using a silica substrate with three graphene sheets.

Conclusions:

• The proposed graphene-based THz biosensor architecture demonstrates significantly improved sensitivity.
• Optimizing graphene configuration and substrate material are crucial for high-performance THz biosensing.
• This work presents a promising platform for sensitive and label-free detection of biomolecules.