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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 27: Postersession KFM

KFM 27.15: Poster

Thursday, March 15, 2018, 15:00–17:00, Poster E

Optimising interferometric displacement detection for NC-AFM operation — •Alexander von Schmidsfeld and Michael Reichling — Universität Osnabrück

We systematically describe the steps needed for optimal calibration of interferometric displacement detection of the cantilever in NC-AFM and demonstrate that the interferometer for displacement detection can be operated in both, the Michelson and the Fabry-Perot mode. After describing the basic interferometer setup, we present a method to characterize the optical losses occurring in the feed line and the results of deficient fiber-cantilever alignment. Furthermore, we introduce the method of 3D intensity mapping of the optical cavity response and recordings of the interferometer signal as a function of the fiber-end-to-cantilever distance, both together allowing us to optimize the adjustment. Finally we examine the impact of opto-mechanical effects occurring in a cavity of sufficient finesse on the detection noise figures and the effective parameters of the cantilever oscillation, namely the Q-factor Q0 and the stiffness k0, both split into values for positive and negative fringes of the interferogram, respectively.