Tunable multifunctional terahertz metasurface based on an indium antimonide medium

Area of Science:

• Metamaterials and Nanophotonics
• Terahertz (THz) Technology
• Condensed Matter Physics

Background:

• Active adjustable terahertz multifunctional devices are essential for advancing terahertz technology applications.
• Current terahertz devices often lack the flexibility for diverse functional switching.
• Metasurfaces offer a promising platform for manipulating electromagnetic waves.

Purpose of the Study:

• To propose and demonstrate a novel composite metasurface for tunable terahertz wave manipulation.
• To achieve multifunctional switching in a single terahertz device by controlling material phase states.
• To enable flexible regulation of terahertz waves for various applications.

Main Methods:

• Design of a composite metasurface utilizing an indium antimonide (InSb) metal octagonal pattern.
• Control of the InSb phase state (dielectric and metallic) via ambient temperature.
• Encoding of unit cells to achieve different terahertz wave functionalities.
• Investigation of device performance for both circularly polarized (CP) and linearly polarized (LP) terahertz waves.

Main Results:

• Demonstrated multifunctional switching by controlling the temperature-dependent phase state of InSb.
• When InSb is in the dielectric state, the metasurface exhibits two-beam splitting, vortex beam superposition, and dual vortex beam superposition for CP and LP waves.
• When InSb is in the metallic state, the metasurface alters its modulation function for incident CP and LP terahertz waves.

Conclusions:

• The proposed InSb-based metasurface offers a new pathway for designing actively tunable and multifunctional terahertz devices.
• The temperature-controlled phase transition of InSb provides a mechanism for flexible terahertz wave regulation.
• This work contributes to the development of advanced terahertz systems with reconfigurable functionalities.