We have searched for large deviations from Newtonian gravity by means of a microcantilever-based Cavendish-style experiment. Our data eliminate from consideration mechanisms of deviation that posit strengths ~10^4 times Newtonian gravity at length scales of 20 microns. This measurement is 3 orders of magnitude more sensitive than others that provide constraints at similar length scales.
@article{arxiv.hep-ph/0209325,
title = {New Experimental Constraints on Non-Newtonian Forces below 100 microns},
author = {J. Chiaverini and S. J. Smullin and A. A. Geraci and D. M. Weld and A. Kapitulnik},
journal= {arXiv preprint arXiv:hep-ph/0209325},
year = {2008}
}