  We propose a technique, using interferometry of Bose-Einstein condensed
alkali atoms, for the detection of sub-micron-range forces. It may extend
present searches at 1 micron by 6 to 9 orders of magnitude, deep into the
theoretically interesting regime of 1000 times gravity. We give several
examples of both four-dimensional particles (moduli), as well as
higher-dimensional particles -- vectors and scalars in a large bulk-- that
could mediate forces accessible by this technique.
