  The light-cone Photon wave function in explicit helicity states, valid for
massive quarks and in both momentum and configuration space, is presented by
considering the leading order photon-proton hard scattering, i.e., the
splitting quark pair scatters with the proton in the Regge limit. Further we
apply it to the diffractive scattering at nonzero momentum transfer and reach a
similar factorization as in the case of zero momentum transfer.
