Short Pulse X-Ray Laser at 32.6 nm Based on Transient Gain in Ne-like Titanium

A novel two-step excitation scheme for an efficient table-top x-ray laser has been realized for the first time. A nanosecond pulse creates a plasma of neonlike ions of titanium, followed by a subpicosecond pulse which excites a nonstationary population inversion. With only a few joules of pump energy, a compact x-ray laser at 32.6 nm with a very high gain coefficient of $g=19\mathrm{}{\mathrm{cm}}^{-1\mathrm{}}$ and a gain-length product of $gL=9.5\mathrm{}$ was achieved.