Dynamic loading experiments are described using nanosecond scale laser pulses of 2 to 1000 GW/cm2over a region 5 mm in diameter. The laser irradiance was tailored to generate shocks or quasi‐isentropic compression. The experiments include novel diagnostic techniques with high temporal resolution: transient x‐ray diffraction (TXD) and polarization‐dependent reflectivity (ellipsometry). TXD uses a laser‐produced plasma to form an x‐ray source. These x rays are collimated by a pinhole to form a Bragg scattering source, which allowed powder lines to be detected from polycrystalline samples such as beryllium foils. Ellipsometry has been demonstrated with 50 ps resolution using the reflectance of a pulsed 660 nm laser from silicon and tin samples through lithium fluoride windows. Ellipsometry can indicate phase changes and potentially yields estimates of surface temperature via the dielectric conductivity. The combination of TXD and ellipsometry with VISAR measurements provides precision characterization of dynamic material properties at high pressures. © 2004 American Institute of Physics