Broadband Three-Mode Tunable Metamaterials Based on Graphene and Vanadium Oxide

Area of Science:

• Condensed Matter Physics
• Materials Science
• Electromagnetics

Background:

• Terahertz (THz) waves offer significant potential for applications like security imaging and wireless communication.
• Efficient and tunable THz-absorbing devices are critical for advancing THz technologies.

Purpose of the Study:

• To propose and investigate a novel tunable THz metamaterial.
• To explore the absorption and transmission characteristics of the metamaterial by adjusting material properties.

Main Methods:

• Fabrication of a metamaterial utilizing graphene and vanadium dioxide.
• Characterization of the metamaterial's absorptivity and transmissivity across a broad THz frequency range.
• Analysis of the influence of vanadium dioxide conductivity and graphene Fermi level on device performance.

Main Results:

• Achieved over 90% absorptivity in an ultra-broadband range (2.05-14.03 THz) under specific conditions (VO2 conductivity = 1.6 × 10^5 S/m, graphene Fermi level = 0.75 eV).
• Demonstrated tunable absorption by adjusting the graphene Fermi level, narrowing the high absorption range (4.07-13.80 THz).
• Exhibited high transmissivity (>80% up to 15 THz) when vanadium dioxide conductivity was reduced (200 S/m).
• Confirmed the metamaterial's insensitivity to polarization and incident angles, enhancing its practical applicability.

Conclusions:

• The proposed graphene-vanadium dioxide metamaterial offers tunable broadband absorption and high transmission properties.
• The device's robustness against polarization and incidence angle variations makes it suitable for real-world applications.
• Potential applications include optical switches, stealth devices, and filtering devices in the THz spectrum.