Small Amplitude Atomic Force Spectroscopy

Over the years atomic force microscopy has developed from a pure imaging technique to a tool that can be employed for measuring quantitative tip–sample interaction forces. In this chapter we provide an overview of various techniques to extract quantitative tip–sample forces focusing on both amplitude modulation and frequency modulation atomic force spectroscopy (AM-AFS and FM-AFS) in the small amplitude regime. We discuss different actuation methods, such as sample modulation, magnetic actuation, and by far the most widely used acoustic driving. Also the corresponding force-inversion methodology is discussed for – in particular – ambient liquid.