In one minute

McGregor, Huang, Shadwick and Batelaan analyse how electron spin behaves as electrons pass through a laser field. With pulsed electron sources synchronised to pulsed lasers becoming available, it is timely to study the weaker coupling of electron spin to laser light. They present an experimentally realisable two-colour Kapitza-Dirac scenario in which spin-dependent effects of the laser-electron interaction dominate. Both the laser strength and electron speed stay non-relativistic. This extends spin control of electrons by light, previously predicted for X-ray lasers and relativistic electrons, into the non-relativistic, visible-light domain. The effect could provide or analyse ultrafast spin-polarised electron pulses for ultrafast electron diffraction and microscopy.

Spin-dependent two-color Kapitza-Dirac effects