A tunable THz absorber consisting of an elliptical graphene disk array.

Area of Science:

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

Background:

• Graphene exhibits unique plasmonic properties in the THz region.
• Tunable absorbers are crucial for various THz applications.

Purpose of the Study:

• To design and investigate an adjustable THz absorber based on elliptical graphene disks.
• To explore the tunability of absorption peaks via structural and electrical parameters.

Main Methods:

• Fabrication of a periodically patterned elliptical graphene disk array.
• Optical characterization using circularly and elliptically polarized THz light.
• Analysis of F-P resonance of graphene edge plasmon modes.

Main Results:

• The absorber exhibits dual absorption peaks in the THz region due to F-P resonance.
• Absorption peak positions are tunable by adjusting the graphene Fermi level.
• Broadband absorption achieved by modifying disk dimensions, with FWHM up to 3.52 THz.
• Tunable peak ratios and conversion from double-band to single-band absorption via polarization control.

Conclusions:

• The proposed graphene-based structure offers a versatile platform for tunable THz absorption.
• The design allows for precise control over absorption characteristics, enabling diverse THz applications.