Single pass density diagnostic for expanded warm dense plasmas*

Warm dense plasmas are opaque to visible light. However, the density gradient of the expanded, less dense plasma surrounding the warm dense matter (WDM) can be optically accessed. This paper describes the development and implementation of Moir\'{e} deflectometry and Nomarski interferometry techniques for analysis of the expanded WDM produced from an intense electron beam on a thin foil. The 20 MeV beam incident on copper or titanium targets produce plasmas where the densities are \textless 8 x 10$^{\mathrm{22\thinspace }}$cm$^{\mathrm{-3}}$. The measurements rely on a probe laser of wavelength 405 nm in which the critical density is \textasciitilde 7 x 10$^{\mathrm{21}}$ cm$^{\mathrm{-3}}$, meaning a large portion of the plasma is accessible. Preliminary maps of the density gradient obtained by Moir\'{e} deflectometry and the density by Nomarski interferometry will be presented. In addition, the characterization, development, and implementation of these techniques are applied to atmospheric plasma sources.