High-power cadmium photoionization laser pumped by soft x rays from a laser-produced multispot plasma

Soft x rays from as many as nine plasma spots, produced by a 1-J, 8-nsec Nd:YAG laser system, have been used to excite Cd atoms by inner-shell photoionization and to generate high-power laser radiation in Cd(+) at 442 and 325 nm. With our multifoci setup a strong reduction of photoelectron impact and radiation losses during the excitation and laser process was possible, resulting in Cd(+) laser output energies (peak powers) as high as 1.1 mJ (85 kW) at 442 nm and 140 microJ (11 kW) at 325 nm, which are, to our knowledge, the highest achieved to date.