Soft X-Ray Amplification at 26.2 nm with 1-Hz Repetition Rate in a Table-Top System

Using a very small Nd/YAG pumping laser (0.45 J in 8 nsec), we have demonstrated high gain $(G\approx 14–19\mathrm{cm}{}^{-1\mathrm{}})$ and gain-length product $(\mathrm{GL}\ge 5)$ in hydrogenlike B V ions at a wavelength of 26.2 nm (the 3-2 transition) at a repetition rate of 1 Hz. The preplasma in a ${\mathrm{B}}_2{\mathrm{O}}_3$ microcapillary was created from wall ablation with a 0.2-J (in 20 nsec) KrF laser. The gain was generated in the microcapillary plasma in a traveling wave regime by longitudinal pumping. This very efficient soft x-ray lasing system takes up less space than is available on a $4\mathrm{ft}\times 10\mathrm{ft}$ optical table.