title: Improved beam characteristics of solid-target soft x-ray laser amplifiers by injection seeding with high harmonic pulses.
abstract: Injection seeding of solid-target soft x-ray laser amplifiers with high harmonic pulses is shown to dramatically improve the far-field laser beam profile and reduce the beam divergence. Measurements and two-dimensional simulations for a 13.9 nm nickel-like Ag amplifier show that the amplified beam divergence depends strongly on the seed and can therefore be controlled by selecting the divergence of the seed. The near-field beam size of both the seeded and unseeded lasers is shown to be determined by the size of the gain region and the divergence of the amplified beams.
authors.affiliation: National Science Foundation Engineering Research Center for Extreme Ultraviolet Science and Technology, Colorado State University, Fort Collins, Colorado 80523, USA. berrill@engr.colostate.edu
authors.forename: Mark
authors.initials: M
authors.lastname: Berrill
authors.forename: David
authors.initials: D
authors.lastname: Alessi
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Scott R
authors.initials: SR
authors.lastname: Domingue
authors.forename: Dale H
authors.initials: DH
authors.lastname: Martz
authors.forename: Brad M
authors.initials: BM
authors.lastname: Luther
authors.forename: Yanwei
authors.initials: Y
authors.lastname: Liu
authors.forename: Jorge J
authors.initials: JJ
authors.lastname: Rocca