SHOCK WAVES IN MOLECULAR SOLIDS - ULTRAFAST VIBRATIONAL SPECTROSCOPY OF THE FIRST NANOSECOND

摘要

A novel technique which uses a microfabricated shock target array assembly is described, where the passage of a shock front through a thin (0.5 mu m) polycrystalline layer and the subsequent unloading process is monitored in real time with ultrafast coherent Raman spectroscopy. Using a high repetition rate laser shock generation technique, high resolution, coherent Raman spectra are obtained in shocked anthracene and in a high explosive material, NTO, with time resolution of similar to 50 ps, Spectroscopic measurements are presented which yield the shock pressure (up to 5 GPa), the shock velocity (similar to 4 km/s), the shock front rise-time (t(r) < 25 ps), and the temperature (similar to 400 degrees C). A brief discussion is presented, how this new technique can be used to determine the Hugoniot, the equation of state, the entropy increase across the shock front, and monitor shock induced chemical reactions in real time. [References: 34]