Condensed Matter Physics Seminar

Prof. David Haviland, Royal Institute of Technology (KTH), Stockholm, Sweden

Friday 23 January 2015, 1500-1600
C1 Physics Building

The Nonlinear dynamics of high Q oscillators - with applications to Atomic Force Microscopy

The high quality factor of a mechanical resonator is often used to detect very weak forces, for example in dynamic Atomic Force Microscopy (AFM). Near resonance the steady-state response (amplitude and phase) of the resonator becomes extremely sensitive to small perturbations. For AFM the force detection sensitivity near resonance is at the fundamental thermal-noise limit. Resonant detection often relies on nonlinearity, where the perturbing force results on a nonlinear dynamics of the resonator. This talk will describe how the measurement and analysis of high-order intermodulation, or frequency mixing of multiple drive tones, allows one to reconstruct the perturbing nonlinearity. The intermodulation spectral method is a powerful new paradigm for enhancing many types of measurements based resonant detection, and it is presently resulting in new understanding of tip-surface interactions in AFM.