  We propose a novel setup to investigate the quantum non-locality of orbital
angular momentum states living in a high-dimensional Hilbert space. We
incorporate non-integer spiral phase plates in spatial analyzers, enabling us
to use only two detectors. The resulting setup is somewhat reminiscent of that
used to measure polarization entanglement. However, the two-photon states that
are produced, are not confined to a 2X2-dimensional Hilbert space, and the
setup allows the probing of correlations in a high-dimensional space. For the
special case of half-integer spiral phase plates, we predict a violation of the
Clauser-Horne-Shimony-Holt version of the Bell inequality (S<=2), that is even
stronger than achievable for two qubits (S=2*(2^1/2)), namely S=16/5
