RANDOM-PHASE PLATES FOR BEAM SMOOTHING ON THE NOVA LASER

We discuss the design and fabrication of 80-cm-diameter random phase p lates for target-plane beam smoothing on the Nova laser. Random phase plates have been used in a variety of inertial confinement fusion targ et experiments, such as studying direct-drive hydrodynamic stability a nd producing spatially smooth x-ray backlighting sources. These phase plates were produced by using a novel sol-gel dip-coating technique de veloped by us. The sol-gel phase plates have a high optical damage thr eshold at the second- and third-harmonic wavelengths of the Nd:glass l aser and have excellent optical performance.