Yoshiaki Kato has engaged in the development and application of high-power lasers at ILE/Osaka and KPSI/QST. He has initiated using the Nd-doped phosphate glass in the highpower Nd:glass lasers for laser fusion research. The “random-phasing” of the high-power laser he has proposed, has stimulated developing further approaches to reduce the coherence, and became an essential method for uniform irradiation and plasma instability suppression in the direct-drive and indirect-drive laser fusion. Also he has pioneered in introducing CPA to the high-power Nd:glass laser, opening the research in laser wakefield electron acceleration, short-pulse driven x-ray lasers, and fast-ignition laser fusion. These works have stimulated JAERI (now QST) to start KPSI on the T3 concept which Prof. Gerard Mourou has proposed. Recently Yoshiaki Kato is interested in the possibility of developing an EW-class laser.

    High power laser has evolved from kJ-MJ, ~ns Nd:glass lasers for laser fusion to 0.1-10 PW, ~10s-fs CPA Ti:sapphire lasers for high field science. Furthermore, a 100PW, ~10fs OPCPA laser is being developed for extreme field science at SIOM. Recent finding of suppression of small-scale self-focusing at IAP/RAS may lead to post compression a feasible approach for generating over 100 PW. Various types of x-ray lasers have been developed using these highpower lasers as drivers. Repetitive x-ray lasers may be realized by driving with the repetitively pulsed high-energy laser developed at RAL. In this presentation, I will briefly review the development of high-power lasers and x-ray lasers I have involved in at ILE/Osaka, KPSI/QST, and more recently at ELI-Beamlines, and explore possibilities opened by advanced high-power lasers.