Coherent anti-Stokes Raman scattering of laser shock compressed α-quartz

Abstract

We have developed the capability to perform in situ coherent anti-Stokes Raman scattering (CARS) spectroscopy on materials that are dynamically compressed using the Janus laser at Lawrence Livermore National Laboratory. We measured the CARS spectrum of α-quartz that was shocked above the Hugoniot elastic limit along the c-axis to 19.0 GPa. These data show that the Si-O-Si angle, which is natively 144° becomes a distribution of angles ranging from 139° to 146°. The data also observe a significant increase in the broad peak above 600 cm -1 that is attributed to defects in amorphous silica. Previous studies have shown these features in shock recovered α-quartz samples that have undergone varying amounts of amorphization, and these data show strong evidence of amorphization of quartz at a pressure below that of the amorphization observed in the shock-recovered samples. © 2012 American Institute of Physics.