Study of Shock-Induced Phase Transformations in Silicon using Ultrafast Dynamic Ellipsometry

POSTER

Abstract

The kinetics of shock-induced phase transformations are currently being investigated using ultrafast dynamic ellipsometry (UDE), which measures relative changes in optical phase and reflectivity. In this work, thin films (400 nm - 1.5 um) of crystalline and amorphous silicon are shock-compressed using a Ti-sapphire, shaped-pulse ultrafast laser system. UDE and an accompanying thin-film analysis are employed to track the motion of the shock-front, and provide evidence of structural phase transformations and/or metallization transitions in silicon. Results suggest a complex time-dependent change in the dielectric function within the 250 ps diagnostic lifetime, indicative of transformation kinetics.

Authors

  • Dan Eakins

    Los Alamos National Laboratory, DE-9, Los Alamos National Labs, Los Alamos, NM

  • Cindy Bolme

    Los Alamos National Laboratory, DE-9, Los Alamos National Labs, Los Alamos, NM

  • Shawn McGrane

    Los Alamos National Laboratory, DE-9, Los Alamos National Labs, Los Alamos, NM

  • David Moore

    Los Alamos National Laboratory, Los Alamos National Lab, DE-9, Los Alamos National Labs, Los Alamos, NM