MULTIPHOTON ANGULAR-DISTRIBUTIONS WITH ELLIPTICALLY POLARIZED-LIGHT .1. ANALYTIC ELLIPTICITY DEPENDENCE OF PHOTOELECTRON DISTRIBUTIONS IN THE POLARIZATION-PLANE

Multiphoton excitation with elliptically polarized light brings out more information in the photodetachment or photoionization processes than linearly polarized light. This information can only be reached, however, by recording photoelectron angular distributions for several values of the ellipticity angle, and fitting the data with a common formula. But the analytic dependence of photoelectron angular distributions on the ellipticity has been unknown up to now, except for the one- and two-photon excitation cases. Here we give a demonstration of a general formula, valid for any number N of exciting photons, with the assumptions of (i) an initially even and momentumless (J = O) atom or ion and (ii) that after excitation of an electron, the residual core is left in an odd state. Slight modifications in the demonstration would make it possible to extend the general formula to any J = O initial atomic state.