Microstructural Acoustics and Picosecond Ultrasonics

Picosecond pulsed lasers provide a convenient source of acoustic waves with frequencies in the GHz range and with wavelengths between one and several hundred microns. This project seeks to develop and use these laser-based tools to study the high frequency acoustic responses of structures with characteristic dimensions that are similar to the acoustic wavelengths: thin films and membranes, multilayer stacks, microfluidic networks, etc. Analysis of these measurements yields intrinsic mechanical and thermal properties on micron length scales. These methods can also be used for basic studies of phononic bandgaps and other interesting acoustic phenomena in micro and nanofabricated structures.