Dynamically tunable broadband absorber/reflector based on graphene and VO₂ metamaterials

Area of Science:

• Metamaterials and Nanophotonics
• Infrared Spectroscopy
• Advanced Materials

Background:

• Metamaterial absorbers and reflectors are crucial for optical devices.
• Tunable materials like vanadium dioxide (VO2) and graphene offer dynamic control over electromagnetic properties.
• Developing difunctional devices with both absorption and reflection capabilities is a key research area.

Purpose of the Study:

• To propose and analyze a novel difunctional tunable broadband absorber/reflector.
• To investigate the dynamic tunability of the device based on graphene and VO2 properties.
• To explore potential applications in infrared spectroscopy and environmental monitoring.

Main Methods:

• Numerical simulations were employed to analyze the optical performance of the proposed device.
• The device design consists of a periodic cross-shaped graphene array coupled with a vanadium dioxide (VO2) layer.
• The tunability was investigated by varying the Fermi energy level of graphene and the temperature-dependent properties of VO2.

Main Results:

• The device demonstrated high absorption (>90%) over a broad bandwidth (56.1-59.0 THz) in absorber mode.
• Significant absorption (>80%) was also observed in another frequency range (88.5-90.2 THz).
• Dynamic tuning of absorption and reflection properties was confirmed through simulations.

Conclusions:

• The proposed graphene-VO2 metamaterial exhibits excellent broadband absorption and reflection capabilities.
• The device's tunable nature, owing to graphene and VO2, makes it suitable for dynamic optical applications.
• Potential applications include infrared spectrophotometers, on-dispersive infrared photometers, Fourier transform infrared spectrometers, and environmental monitoring.