Ni-like x-ray lasers resonantly photopumped by Ly-α radiation

This Letter proposes a new class of x-ray lasers that lase on several 4d{→}4p transitions ranging from 23 to 80 {} in Ni-like ions with atomic number Z=72 to 90 and are resonantly photopumped by Ly-{α} radiation from corresponding H-like ions with atomic number (Z-21)/3. This scheme is unique in that it consists of a family of resonant pairs working off the ground state of the laser ion. Calculations of the gain of these laser transitions in steady-state equilibrium plasmas are presented.