  Partial-transfer absorption imaging is a tool that enables optimal imaging of
atomic clouds for a wide range of optical depths. In contrast to standard
absorption imaging, the technique can be minimally-destructive and can be used
to obtain multiple successive images of the same sample. The technique involves
transferring a small fraction of the sample from an initial internal atomic
state to an auxiliary state and subsequently imaging that fraction absorptively
on a cycling transition. The atoms remaining in the initial state are
essentially unaffected. We demonstrate the technique, discuss its
applicability, and compare its performance as a minimally-destructive technique
to that of phase-contrast imaging.
