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Thursday, August 02, 2012
2:00 PM - 2:45 PM
CNLS Conference Room (TA-3, Bldg 1690)

Postdoc Seminar

Engineering Casimir force reduction through metallic surface nanostructuring

Francesco Intravaia

The Casimir force is an interaction arising from quantum-mechanical fluctuations of the electromagnetic (EM) field, and is technologically significant as it results in stiction in micro- and nano-electromechanical systems (MEMS and NEMS). Control of the Casimir force has remained elusive, as many complex EM modes over a broad range of energy and length scales contribute simultaneously. Here we engineer one of two interacting gold surfaces into a high aspect ratio lamellar grating with 100 nm features, and experimentally demonstrate for the first time a strong Casimir force reduction by metallic nanostructuring. For inter-surface separations d above 400 nm, the measured Casimir force in vacuum decreases faster than the usual power-law reaching a value more than 2 times smaller than the one predicted by the proximity force approximation for planar-like geometries. Our experimental findings pave the way towards control and neutralization of Casimir forces for stiction mitigation in MEMS and NEMS. The observed force suppression is, however, in disagreement with our ab-initio numerical analysis, which treats the curvature of the force probe (a large metallic sphere) in the proximity force approximation and assumes the grating is infinitely large. We are currently investigating possible causes for the experiment-theory disagreement, for example finite size effects.

Host: Kipton Barros, T-4 and CNLS