Ellipsometry in the study of dynamic material properties

Measurements of the time-dependent absolute temperature of high-explosive (HE) shocked surfaces provide valuable constraints on the equations-of-state (EOS) of materials and of the state of ejecta from those surfaces. In support of these dynamic surface temperature measurements, we are developing techniques for measuring the dynamic surface emissivity of shocked metals in the near-infrared (IR). These consist of time-dependent laser polarimetric measurements, using several approaches. We include here a discussion of these polarimeter techniques. Polarimetry permits an accurate determination of the dynamic emissivity at a given wavelength, and may also provide a signature of melt in shocked metals.