Saturated Ni-like Ag x-ray laser at 13.9 nm pumped by a single picosecond laser pulse

A demonstration of a transient collisional x-ray laser pumped by only a single profiled picosecond laser pulse is reported. Saturated operation on the $4d-4p$ transition in Ni-like silver at 13.9 nm is demonstrated using a pump energy of less than 3 J, i.e., more than halved in comparison to the best achievements in the double-pulse scheme. The pump laser pulse characteristics, traveling excitation wave, and x-ray output are discussed as well.