We show that the spatial coherence of a partially incoherent light beam can
be greatly enhanced through an energy-conserving interaction with an incoh
erent or a coherent dark spatial soliton. Computer simulations show that du
ring this process a portion of the incoherent beam is trapped within the da
rk notch of the dark soliton, thus forming a sharp intensity spike. In this
region the correlation length dramatically increases by at least 2 orders
of magnitude. (C) 2000 Optical Society of America.