We report recent investigations of optical field ionization soft-x-ray lasers. We generated the amplifying medium by focusing a circularly polarized 760-mJ, 30-fs 10-Hz Ti:sapphire laser system into a gas cell a few millimeters long filled with xenon or krypton gas. A gain of 67 cm<sup>−1</sup> on the 4d<sup>9</sup>5p–4d<sup>9</sup>5d transition at 41.8 nm in Pd-like xenon and a gain–length product of 15 have been inferred at saturation. This source delivers ∼5×10<sup>9</sup> photons per pulse. More recently we demonstrated lasing at 32.8 nm in Ni-like krypton. The influence of the pumping energy and the laser polarization on the lasing output as well as on the far-field pattern of the x-ray laser beam are reported and discussed.
© 2003 Optical Society of America
(140.0140) Lasers and laser optics : Lasers and laser optics
(140.7240) Lasers and laser optics : UV, EUV, and X-ray lasers
(340.7480) X-ray optics : X-rays, soft x-rays, extreme ultraviolet (EUV)
Stéphane Sebban, Lee M. Upcraft, Philippe Balcou, Moana Pittman, Romain Haroutunian, Georges Grillon, Constance Valentin, Antoine Rousse, Jean-Philippe Rousseau, Laurent Notebaert, Danièle Hulin, Tomas Mocek, Bedrich Rus, David Ros, Annie Klisnick, Antoine Carillon, and Gérard Jamelot, "Investigations of collisionally pumped optical field ionization soft-x-ray lasers," J. Opt. Soc. Am. B 20, 195-202 (2003)