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Graduate Student Seminar - 10/19/2012

"Frequency-Modulation Measurement of the Casimir Force between a Gold Sphere and Sample"

by Joseph Garrett

Friday, October 19, 2012 -- 12:00 p.m.
Large Conference Room, 1207 Energy Research Facility

Advisor:  Assistant Professor Jeremy Munday

The Casimir force arises from the interactions between fluctuating dipoles in two media separated by a gap. We measure the height derivative of the Casimir force between a gold-coated sphere and a gold surface using the noncontact frequency-modulation (FM) method of atomic force microscopy (AFM). The resonant frequency of the cantilever is tracked as the sphere is brought close to the surface. At each distance from the surface, the bias voltage of the sphere is swept, both to measure the distance between the sphere and the surface and to mitigate the effect of any contact potential difference. We discuss the effects of cantilever deflection, contact potential differences, and techniques to compensate for these effects.

For additional information about the IREAP Graduate Student Seminars, contact David Meichle.

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