Resonant photoexcitation as a pumping mechanism for far ultraviolet lasers

A theoretical study is made of the possibility of attaining gains of 2–10 cm^–1 for transitions of hydrogen-like ions in the spectral range of a few tens of nanometers by resonant photoexcitation of the upper active level. A system with a "lamp" spatially separated from an active medium is considered. Detailed numerical estimates are obtained for the V XV–Li III resonance pair and these estimates indicate that a sufficiently high gain should be attainable in relatively simple plasma apparatus.