Engineering tunable terahertz radiation from an electron bunch using graphene metasurfaces

Area of Science:

• Physics
• Materials Science
• Electrical Engineering

Background:

• Terahertz (THz) radiation generation is crucial for various scientific and technological applications.
• Graphene metasurfaces offer unique electromagnetic properties for manipulating THz waves.
• Controlling THz radiation properties like frequency, amplitude, and direction remains a significant challenge.

Purpose of the Study:

• To propose and investigate a novel approach for generating tunable THz radiation.
• To explore the control of THz radiation frequency, amplitude, and direction using graphene metasurfaces.
• To understand the underlying physical mechanisms of THz generation in this system.

Main Methods:

• Utilizing an electron bunch passing over a specially designed graphene metasurface.
• Modulating the chemical potential of the graphene to tune radiation properties.
• Analyzing the interaction between the electron bunch and surface plasmon polaritons (SPPs).

Main Results:

• Observed tunable THz radiation with frequency controlled by graphene's chemical potential.
• Demonstrated control over THz radiation amplitude and direction.
• Identified a linear relationship between radiation frequency and chemical potential.
• Found an inverse relationship between radiation magnitude and reflection magnitude.
• Attributed strong Smith-Purcell radiation to electron bunch interaction with SPPs.

Conclusions:

• The proposed approach enables tunable THz radiation generation with controllable frequency, amplitude, and direction.
• Graphene metasurfaces are effective for manipulating THz radiation via SPP excitation.
• This work provides a promising pathway for developing advanced tunable THz sources.