Graphene-supported tunable bidirectional terahertz metamaterials absorbers

Area of Science:

• Terahertz (THz) technology
• Condensed matter physics
• Materials science

Background:

• Metamaterial absorbers (MMAs) are crucial for manipulating electromagnetic waves.
• Graphene's unique electronic properties offer potential for tunable THz devices.
• Existing THz MMAs often lack tunability and bidirectional functionality.

Purpose of the Study:

• To investigate tunable propagation characteristics of MMAs in the THz region using asymmetric graphene ellipses.
• To design a bidirectional THz MMA with high absorption and modulation capabilities.
• To explore the potential of graphene-based microstructures for advanced THz applications.

Main Methods:

• Asymmetric graphene ellipses were designed and simulated for THz absorption.
• The influence of Fermi energy level on Fano resonance was analyzed.
• A bidirectional MMA was developed by replacing the metal substrate with a graphene layer.

Main Results:

• Two distinct absorption peaks of 84% and 90% were observed at 1.06 THz and 1.67 THz.
• A high Q factor exceeding 20 and wide-range Fano resonance modulation (>43.8%) were achieved.
• The bidirectional MMA demonstrated 88% absorption in the forward direction and functioned as a reflective modulator (60% amplitude, 85% frequency modulation) in the reverse direction.

Conclusions:

• Asymmetric graphene ellipses enable tunable THz absorption and Fano resonance.
• The developed bidirectional MMA offers versatile functionalities for THz wave manipulation.
• These findings pave the way for novel tunable THz filters, absorbers, and modulators.