Generation of a spin-polarized electron beam by multipole magnetic fields.
The propagation of an electron beam in the presence of transverse magnetic fields possessing integer topological charges is presented. The spin-magnetic interaction introduces a nonuniform spin precession of the electrons that gains a space-variant geometrical phase in the transverse plane proportional to the field's topological charge, whose handedness depends on the input electron's spin state. A combination of our proposed device with an electron orbital angular momentum sorter can be utilized as a spin-filter of electron beams in a mid-energy range. We examine these two different configurations of a partial spin-filter generator numerically. The results of this analysis could prove useful in the design of an improved electron microscope.
Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5. Electronic address: ekarimi@uottawa.ca.
Ebrahim
E
Karimi
CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena, Italy.
Vincenzo
V
Grillo
Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5; Institute of Optics, University of Rochester, Rochester, NY 14627, USA.
Robert W
RW
Boyd
Dipartimento di Scienze Fisiche, Università di Napoli "Federico II", Compl. Univ. di Monte S. Angelo, 80126 Napoli, Italy; Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Napoli, Italy.
Enrico
E
Santamato
Electron vortex beam; Polarized electron beam; Spin-to-orbit conversion