Wednesday, April 21, 1999
Physics Colloquium, University of Massachusetts at Lowell (Lowell, MA)
We track laser-induced phase changes in materials on ultrafast time scales by measuring the material's dielectric function (from near-UV to near-IR) with 100-fs time resolution. Experiments on GaAs excited with intense femtosecond pulses reveal details of the ultrafast electron and lattice dynamics at large excited carrier densities. Future experiments will use our technique to measure the plasma dynamics during femtosecond laser-induced breakdown of transparent materials, a process which has been shown to have several potential applications in micro-machining and data storage.