Abstract : The technique of intensity interferometry is presented as a probe of n-n haloes. After exploring the sensitivity of interferometry to the n-n configuration, it is demonstrated that, owing to the specific characteristics of the halo (principally the low momentum content), this technique can only be employed using a new iterative method which provides access to the intrinsic n-n correlation function. The method has been applied to a simultaneous measurement of the dissociation of the three established two-neutron halo systems, 6He, 11Li and 14Be, and the n-n correlation functions and corresponding source sizes extracted for the first time.