X-ray laser development at the Institute of Laser Engineering, Osaka University with worldwide collaboration

This paper presents a brief review of the x-ray laser development at the Institute of Laser Engineering, Osaka University, implemented with worldwide collaboration. The scaling of the x-ray lasing toward shorter wavelengths has been investigated in the recombination-pumped (RP) and electron-collisional-excitation (CE) pumped x-ray lasers. Extension of the RP x-ray laser close to the water window is described. With the CE x-ray laser, intense lasing of the J = 0-1 line at 19.6 nm in the neon-like Ge ion and lasing over 14.3 – 4.5 nm with the nickel-like ions are reported. Spectroscopic studies of the x-ray lasers are described, including the first observation of polarization of the x-ray laser beam generated by amplified spontaneous emission. The perspective of the plasma-based x-ray lasers is also presented.