Vers un microscope de force de Casimir : mesure quantitative de forces faibles et nanopositionnement absolu

Guillaume Jourdan 1
1 NOF - Nano-Optique et Forces
NEEL - Institut Néel
Abstract : Quantum electromagnetic field fluctuations of the vacuum generate an outstanding mechanical effect between two macroscopic objects, whatever their shapes and materials: the Casimir force. This force has been predicted in 1948 by a dutch physicist who gave it his name. Computation was first carried out with two parallel perfect flat mirrors, separated by gap d.
Since its theoretical prediction, this phenomenon has been the focus of numerous scientific communities, from cosmologists, quantum electromagnetic field or gravitational field theorists to micro/nano mechanical systems designers. On one hand this force raises numerous issues at the interface of gravitation physic and quantum electromagnetic field theory since vacuum energy do not fulfill properly commitments of both theories. On the other hand it plays major role in the operation of submicrometric mechanical devices that are currently under investigation and that are expected to revolutionize the whole microelectronic industry. Current theoretical studies aim at understanding impact of boundary conditions on the behaviour of this quantum phenomenon. Experimental project here developed is motivated by the prospect of monitoring force intensity when altering field matter coupling. To this purpose, the project consisted in designing a specific set up capable of measuring weak force between nanostructured surfaces in order to complement boundary conditions effects studies. Gauthier Toricelli implemented specific force probe during his thesis: it consists of an AFM microlever with a gold coated sphere glued at its end. Theoretical and experimental studies have first been carried out to determine properly its mechanical behaviour when coupling to environment including detection devices. Calibration method is a key point of the present work. Calibration accuracy have to be close to percent range to ensure a reliable theory to experiment comparison. Some Casimir force measurements are displayed at the end of the manuscript: they are in compliance with theoretical model within experimental uncertainties. This work finally demonstrates our ability to studying Casimir force between nanostructured surfaces.
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Submitted on : Wednesday, April 16, 2008 - 5:02:27 PM
Last modification on : Thursday, February 14, 2019 - 1:20:45 AM
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Guillaume Jourdan. Vers un microscope de force de Casimir : mesure quantitative de forces faibles et nanopositionnement absolu. Physique [physics]. Université Joseph-Fourier - Grenoble I, 2007. Français. ⟨tel-00273933⟩

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