Application Description

Multi-frequency techniques in atomic force microscopy (MF-AFM) can discriminate many different contributions from the tip-sample interaction in the form of mechanical, electric, magnetic, or optical responses. MF-AFM is also sensitive to non-linear effects causing a harmonic distortion from the steady-state motion of the oscillating cantilever. As most AFM sensors exhibit different eigenmodes up to a few MHz, the ability to actuate and detect such modes separately can be exploited and adapted to measure various physical phenomena. For example, bimodal excitation, dual-harmonic Kelvin probe, multi-harmonic mode, and many SNOM or tip-enhanced techniques often make use of higher harmonic generation.