Spatially and temporally resolved temperature and shock-speed measurements behind a laser-induced blast wave of energetic nanoparticles

Spatially and temporally resolved temperature measurements behind an expanding blast wave are made using picosecond (ps) N-2 coherent anti-Stokes Raman scattering (CARS) following laser flash heating of mixtures containing aluminum nanoparticles embedded in ammonium-nitrate oxidant. Production-front ps-CARS temperatures as high as 3600 +/- 180 K-obtained for 50-nm-diameter commercially produced aluminum-nanoparticle samples-are observed. Time-resolved shadowgraph images of the evolving blast waves are also obtained to determine the shock-wave position and corresponding velocity. These results are compared with near-field blast-wave theory to extract relative rates of energy release for various particle diameters and passivating-layer compositions. (C) 2013 AIP Publishing LLC.