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.
J.A. Rogers, G.R. Bogart and R.E. Miller, “Quantitative Non-Contact Spatial Mapping of Stress and Flexural Rigidity in Thin Membranes Using a Picosecond Transient Grating Photoacoustic Technique”, Journal of the Acoustical Society of America, 109(2), 547-553 (2001).
J.A. Rogers, “Impulsive Stimulated Thermal Scattering”, McGraw-Hill 2002 Yearbook of Science and Technology, (McGraw-Hill, 2002).
L. Dhar and J.A. Rogers, “High Frequency Phononic Crystals Characterized With a Picosecond Transient Grating Photoacoustic Technique”, Applied Physics Letters, 77(9), 1402-1404 (2000).
J.A. Rogers, A.A. Maznev, M.J. Banet and K.A. Nelson, “Optical Generation and Characterization of Acoustic Waves in Thin Films: Fundamentals and Applications”, Annual Reviews of Materials Science, 30, 117-157 (2000).