In this work, the influence of excitation conditions on the performance of a dual-frequency version of tapping-mode atomic force microscopy is studied. In the authors’ previous work, a relationship was identified between the interaction force regime(s) influencing the response of the probe and the specific spectral components observed to be significant in the response. Numerical studies are performed with a three-mode approximation of an atomic force microscope (AFM) probe. This study is conducted by modifying the excitation strength to vary the free response magnitude and the response magnitude ratio, by varying the phase difference between the two excitation components, and by exploring other frequencies for the secondary excitation component. This study reveals undesirable amplitude discontinuities when the influence of the secondary excitation component is too strong, conditions where the accuracy of the relationship is improved, how the selection of the excitation phase difference can influence the results, and the potential of alternative frequency combinations. Through an improved understanding of the relationship, it may provide the means to perform simultaneous imaging and characterization with improved performance using standard AFM systems and AFM probes.

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