Investigation of a strontium vapor laser

An experimental investigation was made of the time dependence of the intensity of spontaneous lines of strontium atoms and ions in an He--Sr plasma formed in 5- and 10-cm diameter discharge tubes. The intensity of the intercombination atomic line (lambda = 689.3 nm) fell on reaching the maximum current. An absorption method was employed to measure the time dependence of the population of the 4d/sup 2/D/sub 5//sub ///sub 2/Sr/sup +/ metastable level which is the lower active level for the lambda = 1033 nm self-terminating transition. Three decay time constants were discovered, depending on the helium pressure p/sub He/. It was found that the decay of the population of the metastable level mainly resulted from collisions with electrons, the most rapid decay of the population with tau/sub 1/ = 1-10 ..mu..sec being due to relaxation of the electron temperature and the slowest decay (with tau/sub 2/ = 10--80 ..mu..sec) due to plasma recombination. At low values of p/sub He/