Angular momentum modulation of vortex Cherenkov radiation in optical waveguides

Area of Science:

• Photonics and Plasmonics
• Quantum Optics
• Free-electron Devices

Background:

• Vortex free-electron radiation shows potential in communications, radiation sources, and particle detection.
• Controlling angular momentum is key to harnessing vortex radiation properties.
• Subwavelength waveguides offer precise control over electromagnetic fields.

Purpose of the Study:

• To investigate the modulation of angular momentum in vortex Cherenkov radiation.
• To explore the use of subwavelength silicon waveguides for this control.
• To demonstrate a novel mechanism for regulating vortex electron radiation.

Main Methods:

• Utilizing subwavelength silicon waveguides to guide electron beams.
• Modulating the topological charge by adjusting the position parameters of two electron beams.
• Investigating the interplay of spin and orbital angular momentum through spin-orbit interaction.
• Analyzing the periodic evolution of angular momenta by breaking waveguide symmetry.

Main Results:

• Angular momentum modulation of vortex Cherenkov radiation was successfully demonstrated.
• Topological charge control was achieved by manipulating electron beam positions.
• Spin-orbit interaction led to the coupling of spin and orbital angular momentum.
• Periodic evolution of spin and orbital angular momenta was observed by breaking symmetry.

Conclusions:

• A novel mechanism for flexibly regulating vortex electron radiation was established.
• The findings open new avenues for electro-optical interaction and device applications.
• This work advances the control over vortex radiation properties for future technologies.