  Using a kinematic approach we show that the non-adiabatic, non-cyclic,
geometric phase corresponding to the radiation emitted by a three level cascade
system provides a sensitive diagnostic tool for determining the entanglement
properties of the two modes of radiation. The nonunitary, noncyclic path in the
state space may be realized through the same control parameters which control
the purity/mixedness and entanglement. We show analytically that the geometric
phase is related to concurrence in certain region of the parameter space. We
further show that the rate of change of the geometric phase reveals its
resilience to fluctuations only for pure Bell type states. Lastly, the
derivative of the geometric phase carries information on both purity/mixedness
and entanglement/separability.
