Optical smoothing techniques for shock wave generation in laser-produced plasmas

Shock wave experiments have been performed at the Laboratoire pour lUtilisation des Lasers Intenses in a regime of interest for inertial confinement fusion and equation of state measurements. Laser beams have been optically smoothed either with random phase plates or with phased zone plates. This last technique allowed the production of a flat-top intensity distribution in the focal spot and hence of flat shock fronts. High quality shocks have been produced and used with stepped targets to allow direct measurements of shock velocity by time-resolved imaging of shock breakthrough at the rear of irradiated targets.