Switchable ultra-broadband terahertz wave absorption with VO₂-based metasurface

Area of Science:

• Terahertz (THz) photonics and metamaterials
• Optoelectronics and nanophotonics

Background:

• Metamaterial absorbers (MMAs) offer unique light manipulation capabilities, particularly in the terahertz (THz) range.
• Existing MMAs often face limitations in bandwidth and tunability, hindering practical applications.
• Developing broadband and tunable THz absorbers is crucial for advanced optical devices.

Purpose of the Study:

• To present a thermally switchable THz metasurface with ultra-broadband absorption and high-transmission capabilities.
• To demonstrate the temperature-dependent optical response of the proposed metasurface.
• To explore the scalability and potential applications of the designed THz device.

Main Methods:

• Utilizing numerical simulations to design and analyze a thermally switchable THz metasurface.
• Investigating the absorption and transmission spectra at different ambient temperatures (room temperature and 358 K).
• Assessing the device's performance concerning incident angle sensitivity and bandwidth tunability.

Main Results:

• At room temperature, the metasurface exhibits high transparency.
• At 358 K, the design achieves ultra-broadband absorption (0.398–1.356 THz) with >90% absorptivity.
• The relative absorption bandwidth reaches 109.2%, with insensitivity to incident angles.
• Bandwidth tunability is demonstrated by altering the metasurface's ring structure.

Conclusions:

• The developed thermally switchable THz metasurface offers a promising solution for ultra-broadband absorption and tunable transmission.
• The device's robustness to incident angles and scalability enhance its practical applicability.
• Potential applications include optical switching, THz imaging, modulation, and filtering.