Semiconductor-based plasmonic interferometers for ultrasensitive sensing in a terahertz regime

Area of Science:

• Plasmonics
• Optoelectronics
• Terahertz (THz) Technology

Background:

• Terahertz (THz) sensing requires highly sensitive and robust devices.
• Mach-Zehnder interferometers (MZIs) are established sensing platforms.
• Plasmonic structures offer unique light-matter interaction for enhanced sensing.

Purpose of the Study:

• To propose and investigate a novel plasmonic semiconductor-based Mach-Zehnder interferometer (MZI) for terahertz (THz) sensing.
• To explore its capability for simultaneous refractive index (RI) and temperature detection.
• To develop a theoretical model for performance prediction and validation.

Main Methods:

• Design of an MZI using a semiconductor layer with a microslit flanked by microgrooves.
• Utilizing surface plasmon polariton waves for THz wave interference.
• Theoretical modeling and finite element method (FEM) for performance analysis.

Main Results:

• Achieved high refractive index (RI) sensitivity of 140,000 nm/RIU (0.42 THz/RIU) and relative intensity sensitivity of 1200%RIU^-1.
• Determined a temperature sensitivity of 1470 nm/K (4.7×10^-3 THz/K).
• Demonstrated the potential for further performance improvement through structural optimization.

Conclusions:

• The proposed plasmonic semiconductor MZI is a promising platform for high-performance THz sensing.
• The device enables sensitive detection of RI and temperature, crucial for various applications.
• This work may facilitate advancements in integrated THz sensing systems and circuits.