Sensing at exceptional point in terahertz metasurfaces

Area of Science:

• Physics
• Metasurfaces
• Terahertz Spectroscopy

Background:

• Exceptional points (EPs) in non-Hermitian systems offer unique properties for sensing.
• Terahertz spectroscopy provides high-resolution, non-destructive analysis.
• Metasurfaces enable tailored electromagnetic responses.

Purpose of the Study:

• To design and investigate a non-Hermitian terahertz metasurface for sensing applications.
• To demonstrate a refractive index sensing scheme utilizing EPs.
• To explore the potential of metasurface-based EPs for tunable on-chip sensors.

Main Methods:

• Proposed a non-Hermitian terahertz metasurface with metallic elements and a vanadium oxide (VO2) strip.
• Tuned geometrical parameters and VO2 conductivity to modulate metasurface responses.
• Investigated dynamic responses near the EP and demonstrated sensing via frequency shift and temperature variation.

Main Results:

• Systematically investigated the dynamic responses of the metasurface at the EP.
• Demonstrated a refractive index sensing scheme based on EP reconfiguration.
• Showcased frequency shift and temperature variation as key sensing indicators.

Conclusions:

• The designed terahertz metasurface effectively utilizes EPs for sensing.
• The proposed sensing scheme shows potential for high-resolution detection in the terahertz range.
• This work facilitates the development of tunable on-chip optical sensors for terahertz applications.