Acoustofluidics 17: theory and applications of surface acoustic wave devices for particle manipulation.

In this paper, number 17 of the thematic tutorial series "Acoustofluidics-exploiting ultrasonic standing waves, forces and acoustic streaming in microfluidic systems for cell and particle manipulation", we present the theory of surface acoustic waves (SAWs) and some related microfluidic applications. The equations describing SAWs are derived for a solid-vacuum interface before generalisations are made about solid-solid and solid-fluid interfaces. Techniques for SAW generation are discussed before an overview of applications is presented.