Ultrasonic atomic force microscopy UAFM

A version of scanning probe acoustic technique was developed as ultrasonic atomic force microscopy (UAFM), where higher order mode cantilever vibration is excited at its base (support). It enables precise imaging of both topography and elasticity of stiff samples such as metals and ceramics, without a need for bonding a transducer to the sample. By virtue of this advantage, a range of unique analysis and hardware has been developed. In this chapter, after briefly summarizing the concept of UAFM, basic mathematical analysis, mechanical, and electronic instrumentation are described, including a noise-free cantilever holder and analogue/digital fast resonance frequency tracking circuit. The final section describes illustrative examples first realized by this technique as an introduction for later chapters of applications (e.g. subsurface defects).