EXPERIMENTAL-EVIDENCE FOR CIRCULAR-DICHROISM IN THE DOUBLE PHOTOIONIZATION OF HELIUM

Circular dichroism in the double photoionization of He by circularly p olarized light has been observed in an angle resolved coincidence expe riment at 93.5 eV photon energy: The use of a transmission multilayer, which acts as, a quarter-wave plate for the linearly polarized incide nt light, together with time-of-flight spectrometers, which enable sim ultaneous detection of all electron pairs, has made the measurements p ossible. The results show strong dependence of the dichroism on the re lative emission angles and the energy sharing between the ejected elec trons in good agreement with our numerical calculations.