We report the first demonstration to our knowledge of multipass amplification of soft x rays. A gain medium of neonlike selenium ions was placed within a resonant cavity composed of a multilayer mirror and a beam splitter designed for normal-incidence use at the 20.63- and 20.96-nm laser lines of the neonlike selenium. The laser-cavity output was time resolved and exhibited three distinct temporal components identifiable as the single-, double-, and triple-pass amplified emission. In these experiments, multipass amplification was limited by the finite duration of the gain medium.
© 1988 Optical Society of America
N. M. Ceglio, D. G. Stearns, D. P. Gaines, A. M. Hawryluk, and J. E. Trebes, "Multipass amplification of soft x rays in a laser cavity," Opt. Lett. 13, 108-110 (1988)