Spin-to-orbital angular momentum conversion and spin-polarization filtering in electron beams

Area of Science:

• Quantum optics
• Particle beam manipulation
• Spin physics

Background:

• Spin-polarized electron beams are crucial for advanced applications.
• Converting spin angular momentum to orbital angular momentum is a key challenge.
• Existing methods for spin manipulation have limitations.

Purpose of the Study:

• To propose a space-variant Wien filter design for manipulating electron beam spin.
• To convert spin angular momentum into orbital angular momentum.
• To create electron vortex beams and develop a spin-polarization filter.

Main Methods:

• Designing a space-variant Wien filter exploiting geometrical phase for spin manipulation.
• Applying the filter to spin-polarized and unpolarized electron beams.
• Integrating the filter with a diffraction element for polarization filtering.

Main Results:

• The proposed Wien filter induces a spin half-turn, converting spin to orbital angular momentum.
• It generates electron vortex beams from spin-polarized electron beams.
• It functions as an effective spin-polarization filter for unpolarized beams when combined with a diffraction element.

Conclusions:

• The space-variant Wien filter offers a novel method for generating electron vortex beams.
• This design provides an efficient way to filter spin polarization.
• The approach is adaptable for neutron and atom beams.