Elektronen-Spinpolarisation bei der Photoionisation unpolarisierter Cäsiumatome mit zirkularpolarisiertem Licht

Abstract

Photoelectrons ejected from cesium atoms by circularly polarized light of certain wavelengths are highly spinpolarized according to Fano's theory. Measurements of the spinpolarization of photoelectrons along the wavelength spectrum are reported. The highest degree of spinpolarization obtained experimentally is 100%. Our results reveal a small deviation from the theoretically predicted spinpolarization. Apart from giving information on the influence of spin-orbit interaction on the photoionization process, the Fano-effect turns out to be a simple and efficient method for producing polarized electron beams. Though not designed as a polarized electron source, our present apparatus yields a beam of 0.3·10⁻¹⁰ Ampere with a polarization of 81 ± 3% when a broad unfiltered spectral band is irradiated.