title: Longitudinal coherence measurements of a transient collisional x-ray laser.
abstract: We present what is to our knowledge the first longitudinal coherence measurement of a transient inversion collisional x-ray laser. We investigated the picosecond output of a Ni-like Pd x-ray laser at 14.68 nm generated by the COMET laser facility at the Lawrence Livermore National Laboratory. Interference fringes were generated with a Michelson interferometer setup in which a thin multilayer membrane was used as a beam splitter. We determined the longitudinal coherence for the 4d1S0 --> 4p1P1 lasing transition to be approximately 400 microm (1/e half-width) by changing the length of one interferometer arm and measuring the resultant variation in fringe visibility. The inferred gain-narrowed linewidth of approximately 0.29 pm is a factor of 4 less than previously measured in quasi-steady-state x-ray laser schemes.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA. smith248@llnl.gov
authors.forename: Raymond F
authors.initials: RF
authors.lastname: Smith
authors.forename: James
authors.initials: J
authors.lastname: Dunn
authors.forename: James R
authors.initials: JR
authors.lastname: Hunter
authors.forename: Joseph
authors.initials: J
authors.lastname: Nilsen
authors.forename: Sebastien
authors.initials: S
authors.lastname: Hubert
authors.forename: Sylvie
authors.initials: S
authors.lastname: Jacquemot
authors.forename: Christian
authors.initials: C
authors.lastname: Remond
authors.forename: Remy
authors.initials: R
authors.lastname: Marmoret
authors.forename: Marta
authors.initials: M
authors.lastname: Fajardo
authors.forename: Philippe
authors.initials: P
authors.lastname: Zeitoun
authors.forename: Laurent
authors.initials: L
authors.lastname: Vanbostal
authors.forename: Ciaran L S
authors.initials: CL
authors.lastname: Lewis
authors.forename: Marie Francoise
authors.initials: MF
authors.lastname: Ravet
authors.forename: Franck
authors.initials: F
authors.lastname: Delmotte