Plasmonic Terahertz Devices and Sensors Based on Carbon Electronics

Area of Science:

• Terahertz (THz) photonics and electronics
• Materials science and engineering
• Nanotechnology

Background:

• Tunable terahertz (THz) photonic devices are crucial for applications like signal modulation and molecular sensing.
• Current methods often use resonator arrays, which can negatively impact sample measurements.
• There is a need for alternative approaches that avoid sample contamination and offer tunable THz properties.

Purpose of the Study:

• To develop an alternative approach for tunable THz devices and sensors using postprocessed nanothickness macro-assembled graphene (nMAG) films.
• To demonstrate the multifunctional applications of nMAG films in THz technology.
• To achieve highly sensitive molecular detection using nMAG-based THz metasurfaces.

Main Methods:

• Postprocessing of nanothickness macro-assembled graphene (nMAG) films to achieve tunable THz conductivity.
• Fabrication of nMAG/dielectric/metal and nMAG/dielectric/nMAG THz Salisbury absorbers.
• Development of nMAG-based THz metasurfaces for sensing applications.
• Utilizing resonant field enhancement and molecule-nMAG interactions for detection.

Main Results:

• Achieved a broad range of THz conductivities in nMAG films, from 1.2 × 10^3 S/m to 4.0 × 10^6 S/m.
• Fabricated THz Salisbury absorbers with tunable reflectance from 0% to 80%.
• Demonstrated diphenylamine detection with a limit of detection of 4.2 pg using nMAG metasurfaces.

Conclusions:

• Wafer-scale nMAG films offer widely tunable THz conductivity, enabling versatile solid-state THz devices.
• nMAG-based THz metasurfaces show promise for highly sensitive molecular sensing.
• The developed nMAG films hold significant potential for high-performance THz electronics, photonics, and sensors.