Recent progress in X-ray laser research in JAEA

Kawachi, Tetsuya; Kishimoto, Maki; Kado, Masataka; Tanaka, Momoko; Hasegawa, Noboru; Ochi, Yoshihiro; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kunieda, Yuichi; Oba, Toshiyuki; Nagashima, Keisuke; Namikawa, Kazumichi*; Namba, Shinichi*; Kato, Yoshiaki* ; Kando, Masaki; Fukuda, Yuji; Pirozhkov, A. S.; Ma, J.*; Daito, Izuru; Chen, L.*; Esirkepov, T. Z.; Ogura, Koichi; Homma, Takayuki; Kotaki, Hideyuki; Faenov, A. Y.; Pikuz, T. A.*; Sagisaka, Akito; Mori, Michiaki; Koga, J. K.; Daido, Hiroyuki; Bulanov, S. V.; Tajima, Toshiki

Recent progress in X-ray laser research in Japan Atomic Energy Agency is reviewed. Using the nickel-like silver soft X-ray laser at the wavelength of 13.9 nm, the application experiments have been conducted in the research fields such as material science, high-density plasma diagnostics, XRL ablation, XRL imaging using single-shot holography and atomic physics. The repetition rate of the XRL beam has been improved from each 10-20 minutes to 0.1 Hz by using new driver laser system with Nd: glass zigzag slab amplifier, and we are now constructing new beam line for the pump-probe measurement of the surface phase-transition by the method of X-ray laser interferometer. In the research activity on the extension of the wavelength region of the X-ray lasers, firstly, the demonstration of novel coherent X-ray generation by "flying mirror" technique is reported. The second is theoretical investigation of the resonance photo-pumping scheme toward water-window region.