Saturation of the gain in phosphate neodymium glass GLS22

An experimental investigation was made of the saturation of the gain experienced by laser pulses of 1 and 25 nsec duration in phosphate neodymium glass GLS22. The energy density in the beam reached 8 J/cm² at the amplifier output. The saturation value of the energy density was found to be independent of the pulse duration and of the energy density in the incident beam (within the investigated range) so that the relaxation time of the lower active level was less than 1 nsec.