Harmonic feedback atomic force microscopy

摘要

Harmonic feedback atomic force microscopy (HF-AFM) includes regulating feedback in oscillating probe atomic force microscopy (AFM) based upon an extracted frequency component of a probe response signal. Feedback in conventional oscillating probe AFM uses the probe response signal as a whole (or at least a driven frequency component of the probe response signal). The extracted frequency of the extracted frequency component of HF-AFM generally is different from any substantially driven frequency that generates the probe oscillation and may be a harmonic of a driven frequency. The regulating may include responding to the strength or weakness of the extracted frequency component such that weakening (or strengthening) of the extracted frequency component contributes positively to a decrease (or an increase) in the average tip-sample distance and contributes negatively to an increase (or a decrease) in the average tip-sample distance.