Manipulating Smith-Purcell Emission with Babinet Metasurfaces.

Area of Science:

• Optics and Photonics
• Metamaterials
• Electron-Photon Interactions

Background:

• The Smith-Purcell effect describes light radiation from electrons moving near periodic structures.
• Traditional gratings offer limited control over the polarization of emitted light.
• Metasurfaces provide novel ways to manipulate electromagnetic waves.

Purpose of the Study:

• To demonstrate control over the polarization state of Smith-Purcell emission using designer Babinet metasurfaces.
• To investigate the role of C-aperture resonators in manipulating electron-beam-induced radiation.
• To enhance the efficiency of Smith-Purcell emission.

Main Methods:

• Utilizing designer Babinet metasurfaces with C-aperture resonators.
• Coupling nonradiative energy from the source current sheet to metasurface dipoles.
• Analyzing the excitation of cross-polarized light due to bianisotropy.

Main Results:

• Achieved powerful control over the polarization state of Smith-Purcell emission.
• Excited cross-polarized light by exploiting the metasurface's bianisotropic nature.
• Increased Smith-Purcell emission efficiency by 84% compared to conventional gratings.

Conclusions:

• Babinet metasurfaces offer unprecedented control over electron-beam-induced emission polarization.
• The findings pave the way for compact, tunable, and efficient light sources and particle detectors.
• This work advances near-field manipulation of electron-photon interactions.