Two bits dual-band switchable terahertz absorber enabled by composite graphene and vanadium dioxide metamaterials

Area of Science:

• Metamaterials and Nanophotonics
• Terahertz Technology
• Condensed Matter Physics

Background:

• Terahertz (THz) absorbers are crucial for various applications, including sensing, imaging, and communication.
• Achieving tunable and switchable absorption in the THz regime remains a significant challenge.
• Existing designs often lack multi-band functionality or precise control over absorption states.

Purpose of the Study:

• To design and demonstrate a 2-bit, dual-band switchable terahertz absorber.
• To achieve four distinct absorption states by dynamically controlling graphene and vanadium dioxide (VO2) metamaterials.
• To validate the design through theoretical analysis and electromagnetic simulations.

Main Methods:

• Utilizing a stacked metamaterial structure combining graphene and VO2.
• Employing electrostatic doping to tune graphene conductivity (Fermi level).
• Leveraging the phase transition of VO2 between insulating and metallic states.
• Performing equivalent circuit modeling and full-wave electromagnetic simulations.

Main Results:

• The proposed absorber exhibits two distinct absorption bands, tunable via graphene and VO2 states.
• Four switchable states were demonstrated: dual-band absorption (0.745-0.775 THz and 2.3-5.63 THz), single-band absorption (lower or upper band), and zero absorption.
• Excellent agreement was found between simulation results and theoretical analysis.

Conclusions:

• The presented design offers a novel and effective approach for creating reconfigurable terahertz absorbers.
• The dual-material, multi-state switching mechanism provides significant flexibility for THz applications.
• This work lays the foundation for advanced tunable terahertz devices and systems.