Above threshold ionization with elliptically polarized light.

We have studied above-threshold multiphoton ionization (ATI) angular distributions in xenon and krypton with elliptical laser polarization. In contrast to previous linear and circular polarization studies, we find that the angular distributions are strongly dependent on the order of the ATI peak, even for very high energy electrons. This provides a new test for non- perturbative theories of atomic photoionization. A generalization of the model of Reiss to accommodate elliptical polarization is found to yield angular distributions which are in reasonable accord with experimental results.