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Title: Casimir Force and In Situ Surface Potential Measurements on Nanomembranes
Authors: Daniel Garcia-Sanchez, King Yan Fong, Harish Bhaskaran, Steve Lamoreaux, and Hong X. Tang

We present Casimir force measurements in a sphere-plate configuration that consists of a high quality nanomembrane resonator and a millimetre sized gold coated sphere. The nanomembrane is fabricated from stoichiometric silicon nitride metallised with gold. A Kelvin probe method is used in situ to image the surface potentials to minimize the distance-dependent residual force. Resonance-enhanced frequency-domain measurements of the nanomembrane motion allow for very high resolution measurements of the Casimir force gradient (down to a force gradient sensitivity of 3N/m). Using this technique, the Casimir force in the range of 100 nm to 2m is accurately measured. Experimental data thus obtained indicate that the device system in the measured range is best described with the Drude model.

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Blobrana


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Title: Casimir force measurements in Au-Au and Au-Si cavities at low temperature
Authors: J. Laurent, H. Sellier, A. Mosset, S. Huant, J. Chevrier

We report on measurements of the Casimir force in a sphere-plane geometry using a cryogenic force microscope to move the force probe in situ over different materials. We show how the electrostatic environment of the interacting surfaces plays an important role in weak force measurements and can overcome the Casimir force at large distance. After minimising these parasitic forces, we measure the Casimir force between a gold-coated sphere and either a gold-coated or a heavily doped silicon surface in the 100-400 nm distance range. We compare the experimental data with theoretical predictions and discuss the consequence of a systematic error in the scanner calibration on the agreement between experiment and theory. The relative force over the two surfaces compares favourably with theory at short distance, showing that this Casimir force experiment is sensitive to the dielectric properties of the interacting surfaces.

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