Measurement of the phase difference between even and odd continuum waves in photoionization of atomic rubidium.

We report improved measurements of asymmetric photoelectron angular distributions resulting from photoionization of atomic rubidium through coherent one-photon and two-photon interactions. Analysis of the asymmetry allows us to determine the phase difference between even- and odd-parity continuum wavefunctions. We discuss calibration of the phase, including field propagation phase shifts and the phase shift upon frequency doubling in a nonlinear crystal.