A quest for more efficient X‐ray lasers: Atomic parameters involved and recent experiments

The output energy of present x‐ray lasers is ≲10−6 of that of the driver laser, for laser‐produced plasma media. A significant improvement is essential for more compact, useful, and less costly devices. Some plasma/atomic processes that may bear on this goal and that deserve attention are described. Some experiments already indicate promise for improved efficiency. One recent one from the RIKEN laboratory (Japan) is described, along with initial attempts at the Naval Research Laboratory (NRL) to duplicate the results.