Investigation of the stimulated emission mechanism in a pulsed bismuth vapor laser

An experimental investigation was made of pulsed laser action due to a transition from a resonance level to a metastable level in a bismuth atom at a wavelength of 472.2 nm. It was found that the annular shape of the stimulated emission spot may be due to the high population of the lower active level under operating conditions. An analysis was made of the processes resulting in population of the metastable level in the discharge and of processes which may improve the population inversion conditions in the wall zones of the discharge.