What can we learn from double-electron emission by one circularly polarized photon?

Using a simple exact analysis of the one-photon optical transition amplitud es for the emission of correlated electron pairs from randomly oriented tar gets it is shown that information on the phase differences of these amplitu des can be obtained by the variation of the helicity of the absorbed photon . Experiments performed with different polarization of the photon can be re lated to each other by analytical formulae that should be used as a consist ency check. The usefulness of this approach is demonstrated by analysing re cent experimental and theoretical data.