Higher-harmonics generation in tapping-mode atomic-force microscopy: Insights into the tip–sample interaction

We present an experimental analysis of the nonlinear tip–sample interaction in tapping-mode atomic-force microscopy by exploiting anharmonic contributions of the cantilever motion. Two aspects of a concept aiming at a full reconstruction of the tip–sample interaction are demonstrated: higher flexural eigenmode vibrations excited by the impact of the oscillating tip on the sample are used to measure the tip–sample interaction time; by imaging at higher harmonics of the driving frequency material contrast is obtained.