Stimulated emission due to transitions in alkaline-earth metal ions

Stimulated emission pulses were recorded for eight new transitions in mixtures of magnesium, calcium, strontium and barium vapors with helium or neon. The most interesting lines were located in the violet and nearultraviolet region (0.4305 and 0.4162 μ for strontium and 0.3737 μ for calcium) for which a gain of tens of decibels was obtained. It was found that the main mechanism of the population of the laser was the recombination of doubly charged metal ions, which were generated by electron impact and by thermal collisions with helium or neon ions. The deexcitation by electron impact played an important role in the depopulation of the laser levels.