Terahertz nonreciprocal and functionality-switchable devices based on dielectric multilayers integrated with graphene...

Area of Science:

• Optoelectronics
• Materials Science
• Photonics

Background:

• Terahertz (THz) nonreciprocal and functionality-switchable devices are crucial for advanced applications.
• Existing devices often rely on magnetic materials, limiting their integration and performance.
• Graphene and vanadium dioxide (VO2) offer tunable electromagnetic properties in the THz regime.

Purpose of the Study:

• To design and theoretically explain a magnetic-free THz unidirectional perfect absorber.
• To demonstrate a device with switchable functionality between a band-pass filter and a perfect absorber.
• To investigate the tunability of device performance using graphene's chemical potential.

Main Methods:

• Fabrication of dielectric-graphene multilayers incorporating a VO2 defect layer.
• Theoretical modeling and simulation of electromagnetic wave propagation.
• Analysis of nonreciprocal transmission and absorption spectra.

Main Results:

• A magnetic-free THz unidirectional perfect absorber was theoretically demonstrated.
• Switchable functionality between band-pass filtering and perfect absorption was achieved.
• Device performance, including working frequencies, was shown to be tunable via graphene chemical potential.

Conclusions:

• The proposed dielectric-graphene-VO2 multilayer structure enables novel magnetic-free THz devices.
• The demonstrated unidirectional perfect absorber and switchable filter/absorber hold promise for integrated THz systems.
• Tunability through graphene offers a pathway for customized THz device design.