Tunable wideband-narrowband switchable absorber based on vanadium dioxide and graphene

Area of Science:

• Metamaterials
• Terahertz (THz) technology
• Condensed matter physics

Background:

• Metamaterial absorbers offer unique electromagnetic properties.
• Tuning absorption characteristics is crucial for advanced THz applications.
• Vanadium dioxide (VO2) and graphene exhibit tunable electrical properties.

Purpose of the Study:

• To propose and numerically verify a tunable THz metamaterial absorber.
• To achieve switchable ultra-broadband and narrow-band near-perfect absorption.
• To explore the potential applications in THz imaging, sensing, and shielding.

Main Methods:

• Numerical simulation using finite element analysis.
• Investigating the phase transition properties of VO2.
• Analyzing the tunability of graphene's Fermi energy.

Main Results:

• Achieved ultra-broadband absorption (>95%) from 2.85-10 THz with metallic VO2 and 0 eV graphene.
• Demonstrated narrow-band near-perfect absorption (>99.5%) at 2.3 THz with insulating VO2 and 0.7 eV graphene.
• Confirmed tunability via VO2 conductivity and graphene Fermi energy, with polarization insensitivity and wide incident angle stability.

Conclusions:

• The proposed VO2-graphene metamaterial absorber offers dynamic control over absorption bandwidth and level.
• The design exhibits robust performance under varying polarization and incidence angles.
• This tunable absorber holds promise for diverse THz technological applications.