  We experimentally studied the spatial coherence of random laser emission from
dye solutions containing nanoparticles. The spatial coherence, measured in a
double-slit experiment, varied significantly with the density of scatterers and
the size and shape of the excitation volume. A qualitative explanation is
provided, illustrating the dramatic difference from the spatial coherence of a
conventional laser. This work demonstrates that random lasers can be controlled
to provide intense, spatially incoherent emission for applications in which
spatial cross talk or speckle limit performance.
