Cavitation as a Microfluidic Tool

Cavitation in confined geometries in particular in narrow gaps prevalent in microfluidic geometries allows for novel applications. Here we will give an overview of successful demonstrations of cavitation as a microfluidic tool. Cavitation can pump and mix liquids very rapidly, move objects such as cells, rupture plasma membranes, probe elastic properties in micro-rheology, study coalescence, and even create arbitrary superpositions of shock waves. In all areas, bubbles are created with a focused laser which allows precise temporal and spatial control. With the usage of digital holography arbitrary configurations of bubbles can be created such as bubble clusters, squarish, toroidal, or even linear cavitation bubbles. Interestingly, even in very narrow gaps of a few tens of microns most of the bubble dynamics can be described with potential flow. This presentation will summarize published work and show current research under progress.