Research on efficient X-ray lasing at XingGuang II Laser Facility

Research on efficient X ray lasing at the XingGuang II Laser Facility has been reviewed, in which lasing at 18.9, 20.3, and 28.5 nm from nickel-like molybdenum, niobium and neon-like chromium ions has been observed by using two 200-ps laser pulses with a total energy of 50 J at 1.053 /spl mu/m. This shows the possibility of extending nickel-like and neon-like X-ray lasing in low-Z elements and paves the may toward small scale X-ray lasers for applications at University laboratories. A comparison has been made of performance of the neon-like chromium soft X-ray lasing at 28.5 nm driven by a double 900-ps pulse at 6 TW/spl middot/cm/sup -2/, with that driven by a double 200-ps pulse at similar irradiance. The double 200-ps pulse has been found to be more efficient to drive the neon-like X ray lasing.