Terahertz Biosensor Based on Mode Coupling between Defect Mode and Optical Tamm State with Dirac Semimetal

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Bulk Dirac semimetals (BDS) are explored as 3D graphene analogs for optical devices.
• Terahertz (THz) biosensors offer label-free detection capabilities for various applications.

Purpose of the Study:

• To propose a tunable and highly sensitive THz biosensor based on a BDS/Bragg reflector multilayer structure.
• To investigate the sensing mechanism and performance of the proposed BDS-based biosensor.

Main Methods:

• Utilizing a multilayer structure combining BDS and Bragg reflector.
• Analyzing the coupling of Optical Tamm State (OTS) mode and defect mode to generate Fano resonance.
• Simulating and optimizing structural and material parameters for maximum sensitivity.

Main Results:

• Achieved a sharp Fano resonance peak due to coupled OTS and defect modes, enhancing sensitivity.
• Demonstrated sensitivity dependence on BDS Fermi energy and sensing medium refractive index.
• Obtained a maximum sensitivity of 1022°/RIU, competitive with traditional Surface Plasmon Resonance (SPR) sensors.

Conclusions:

• The BDS-based multilayer structure shows significant potential for highly sensitive THz biosensing.
• The proposed sensor design offers tunability and high performance, suitable for practical biosensor applications.
• Fabrication feasibility and integration potential support the application of BDS in the biosensor field.