We demonstrate an x-ray laser at a wavelength of 13.9 nm with a beam divergence of 0.2 mrad, which is 1.8 times the diffraction limit. The x-ray laser is generated with two gain media; the seed x-ray pulse from the first medium is amplified in the second medium. The effect of refraction on x-ray propagation is reduced by spatially and temporally controlling the injection of the seed x-ray to the second medium.
© 2003 Optical Society of America
(140.3300) Lasers and laser optics : Laser beam shaping
(140.7240) Lasers and laser optics : UV, EUV, and X-ray lasers
(230.6080) Optical devices : Sources
(350.5400) Other areas of optics : Plasmas
Momoko Tanaka, Masaharu Nishikino, Tetsuya Kawachi, Noboru Hasegawa, Masataka Kado, Maki Kishimoto, Keisuke Nagashima, and Yoshiaki Kato, "X-ray laser beam with diffraction-limited divergence generated with two gain media," Opt. Lett. 28, 1680-1682 (2003)