Soft X-ray gain in hydrogenic ions : Line pumping, ionization pumping and transient excitation
In a plasma containing hydrogenic ions which is irradiated by appropriate X-ray radiation, gain on the n=3 to n=2 (Balmer-alpha) transition can be generated. Depending on the spectrum of the pump radiation, there are two different ways of obtaining the inversion: direct excitation of the upper laser level by line radiation, or ionisation of the hydrogenic ions by broad band radiation with subsequent population of the upper level by recombination. The first part of this paper presents numerical calculations which compare the two pumping methods. The gain is evaluated under idealised conditions, i.e., with a pump spectrum containing only radiation useful for generating an inversion and, under more realistic conditions, with a pump spectrum containing radiation at other frequencies as well. In the second part of the paper the possibility of obtaining Balmer-alpha gain in hydrogenic ions under highly transient conditions is investigated, assuming a pump pulse with a duration comparable to the decay time of the lower laser level. Considerable gain is predicted even for a black-body pump spectrum.
Bibliographic Reference: Article: Applied Physics B, Vol. B50 (1990) pp. 177-185
Record Number: 199011261 / Last updated on: 1994-12-01
Original language: en
Available languages: en