Actively tunable and switchable terahertz metamaterials with multi-band perfect absorption and polarization...

Area of Science:

• Optoelectronics and Photonics
• Materials Science
• Terahertz Technology

Background:

• Metamaterials offer unique electromagnetic properties not found in natural materials.
• Vanadium dioxide (VO2) exhibits a phase transition with tunable electrical properties.
• Graphene possesses excellent electronic and optical characteristics in the terahertz spectrum.

Purpose of the Study:

• To theoretically propose and numerically demonstrate a multi-functional metamaterial.
• To achieve active tunability and switching between different functionalities.
• To explore applications in the terahertz region for optoelectronic devices.

Main Methods:

• Theoretical modeling of a metamaterial structure incorporating VO2 and graphene.
• Numerical simulations to analyze electromagnetic response.
• Investigation of performance under different VO2 phase states (metallic and insulator).

Main Results:

• Metamaterial acts as a multi-band perfect absorber with polarization insensitivity and wide incidence angle tolerance when VO2 is in the metallic phase.
• Metamaterial functions as a polarization converter, achieving simultaneous linear-to-linear and linear-to-circular conversions when VO2 is in the insulator phase.
• High cross-polarization conversion efficiency (∼100%) and complete linear-to-circular conversion (ellipticity ±1) demonstrated at specific terahertz frequencies.

Conclusions:

• The proposed VO2-graphene metamaterial exhibits switchable multi-functionality in the terahertz range.
• This design offers robust performance characteristics, including polarization and incidence angle tolerance.
• Presents a promising platform for developing advanced, multi-functional terahertz optoelectronic devices.