Generation of millijoule-level soft-x-ray laser pulses at a 4-Hz repetition rate in a highly saturated tabletop capillary discharge amplifier

Laser pulses with energies of as much as 1 mJ were generated at a wavelengt h of 46.9 nm by single-pass amplification in a 34.5 cm-long Ne-like Ar capi llary discharge plasma. The large gain-length product of this plasma column allows for soft-x-ray amplification in a highly saturated regime, resultin g in efficient energy extraction. Average laser output pulse energy of 0.88 mJ and peak power of 0.6 MW were obtained at a repetition rate of 4 Hz. Wi th an estimated peak spectral brightness of approximate to 1 x 10(23) photo ns/(s mm(2) mrad(2) 0.01% bandwidth) this tabletop laser is one of the brig htest soft-x-ray sources to date. (C) 1999 Optical Society of America.