Physical Review Letters 94,24 (2005) 240401;
We report the first isoelectronic differential force measurements between an Au-coated probe and two Au-coated films, made out of Au and Ge. These measurements, performed at submicron separations using soft microelectromechanical torsional oscillators, eliminate the need for a detailed understanding of the probe-film Casimir interaction. The observed differential signal is directly converted into limits on the parameters alpha and lambda which characterize Yukawa-like deviations from Newtonian gravity. We find alpha less than or similar to 10(12) for lambda similar to 200 nm, an improvement of similar to 10 over previous limits.
mu-m;; dimensions;; gravity
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