Laser-driven shock wave dynamics probed by femtosecond stimulated Raman spectroscopy

Laser-induced shock waves provide a powerful tool for the study of a wide range of phenomena including high-pressure phase transitions and chemical reactions. In this work, we have integrated femtosecond stimulated Raman spectroscopy (FSRS) into a laser-induced shock wave platform to interrogate shock-induced chemical changes. A thin layer of the sample material (25-100 µm) is confined between two glass substrates. An intense laser pulse is absorbed by the material, launching a shock wave that propagates in the sample plane. The shock wave propagation is imaged using a femtosecond pulse train to extract the shock wave speed and consequently the shock pressure, and to observe time-dependent sample responses. FSRS probe pulses are focused onto the sample in the shocked region, collecting a broadband Raman spectrum in a single-shot with picosecond time resolution. This technique allows coherent vibrational spectroscopic probing of molecular dynamics as well as visualization of macroscopic dynamics resulting from shock loading.