  It is known that a spatially partially coherent light field produces better
imaging contrast compared to a spatially coherent field and that the contrast
increases as the spatial coherence length of the field becomes smaller. The
transverse spatial coherence length of most spatially partially coherent fields
increases upon propagation. As a result, the field produces progressively
decreasing image quality at subsequent transverse planes. By controlling the
propagation of spatial coherence, we demonstrate enhanced image quality at
different transverse planes along the propagation direction through a
scattering medium. Using a source with propagation-invariant spatial coherence
function, we report experimental observations of imaging different transverse
planes with equal contrast over a significant distance. Furthermore, we
generate a spatially partially coherent source that can be tailored to have
minimum-possible transverse coherence area at the plane of the object to be
imaged, and using this source, we demonstrate imaging spatially separated
transverse planes with maximum possible image contrast.
