ABSTRACT
A novel excitation scheme for transient gain in collisionally driven x-ray lasers has been realized. A long prepulse creates a plasma with dominant partition of the desired ions followed by a ps pulse which produces efficiently transient gain. Lasing was achieved in neonlike ions front titanium at 32.6 nm and 29.8 nm as well as from vanadium at 30.4 nm with only few Joules of pump energy. On the 3p-3s transition in Ti a very high gain coefficient of g = 19 cm−1 and a gain length product of about 10 was measured. The experimental data provide information for further improvement of this excitation scheme.
