Switchable terahertz metamaterial absorber with broadband absorption and multiband absorption.

Area of Science:

• Physics
• Materials Science
• Electrical Engineering

Background:

• Vanadium dioxide (VO2) exhibits a unique phase transition property, enabling tunable optical and electrical characteristics.
• Terahertz (THz) absorbers are crucial components in various applications, including sensing, imaging, and communications.
• Developing absorbers with switchable functionalities is essential for advanced THz devices.

Purpose of the Study:

• To propose and design a terahertz bifunctional absorber with switchable broadband and multiband absorption capabilities.
• To investigate the absorption mechanisms based on the phase transition of VO2 and the properties of graphene.
• To explore the potential applications of the designed absorber in intelligent absorption and THz switches.

Main Methods:

• A terahertz absorber structure comprising VO2, a topas spacer, metallic disks, and graphene was designed.
• Electromagnetic simulations were performed to analyze the absorption performance under different conditions.
• The phase transition of VO2 (metal and dielectric states) and the Fermi energy level of graphene were varied to tune the absorption properties.

Main Results:

• The designed absorber achieved broadband absorption (>90%) from 3.25 THz to 7.08 THz in the metallic state of VO2, with stable performance up to 50° incident angle.
• In the dielectric state of VO2, the absorber exhibited multiband absorption with six distinct peaks, tunable via the Fermi energy level of graphene.
• The interplay between VO2 phase transition and graphene properties enabled dynamic control over absorption characteristics.

Conclusions:

• A terahertz bifunctional absorber with switchable broadband and multiband absorption functionalities was successfully demonstrated.
• The proposed design leverages the phase transition of VO2 and graphene's tunability for versatile absorption control.
• The developed absorber holds promise for advanced applications in intelligent terahertz systems and switching devices.