Time-resolved reflectivity and transmission measurements of a laser-heated ultrathin foil

Summary form only given. Heating ultrathin foils with femtosecond laser pulses provides an experimental test ground for the study of high-energy density matter, in particular, for warm dense matter (WDM). Investigating the optical properties with high temporal and spatial resolution yields information about the AC conductivity of these nearly isochorically heated states. Theoretical predictions for the optical properties in this WDM regime, i.e., the strongly coupled, partially ionized plasma regime, differ significantly depending on the conductivity and equation of state models used. Thus, gaining experimental access to the optical properties is an important step for guiding empirical models and for testing ab-initio calculations. Measurements - performed at the Ultrashort Pulse laser facility at the Lawrence Livermore National Laboratory - of the reflectivity and the transmission for S- and P-polarized 800-mn light of a 20 nm thin aluminum foil which is being heated by a 100-fs, 400-nm laser pulse will be presented. The measurements also provide the experimental determination of the energy density deposition which is an important constraint with respect to the comparison between the experiment and simulations.