  We explore the influence of elliptical polarization on the (non)sequential
two-photon double ionization of atomic helium with ultrashort extreme
ultraviolet (XUV) light fields using time-dependent full ab-initio simulations.
The energy and angular distributions of photoelectrons are found to be strongly
dependent on the ellipticity. The correlation minimum in the joint angular
distribution becomes more prominently visible with increasing ellipticity. In a
pump-probe sequence of two subsequent XUV pulses with varying ellipticities,
polarization tagging allows to discriminate between sequential and
nonsequential photoionization. This clear separation demonstrates the potential
of elliptically polarized XUV fields for improved control of electronic
emission processes.
