title: Accurate target-plane focal-spot characterization in high-energy laser systems using phase retrieval.
abstract: Target-plane intensities on the short-pulse beamlines of OMEGA EP, a petawatt-class laser, are characterized on-shot using the focal-spot diagnostic (FSD), an indirect wavefront-based measurement. Phase-retrieval methods are employed using on-shot and offline camera-based far-field measurements to improve the wavefront measurements and yield more-accurate, repeatable focal-spot predictions. Incorporation of these techniques has improved the mean cross-correlation between the FSD predictions and direct far-field fluence measurements in the target chamber from 0.78 to 0.94.
authors.affiliation: University of Rochester Laboratory for Laser Energetics, 240 E. River Rd., Rochester, New York 14623, USA. bkru@lle.rochester.edu
authors.forename: B E
authors.initials: BE
authors.lastname: Kruschwitz
authors.forename: S-W
authors.initials: SW
authors.lastname: Bahk
authors.forename: J
authors.initials: J
authors.lastname: Bromage
authors.forename: M D
authors.initials: MD
authors.lastname: Moore
authors.forename: D
authors.initials: D
authors.lastname: Irwin