Investigation of an I2(D'–A') laser pumped by wide-band radiation

An experimental investigation was made of an ultraviolet I₂ laser with an energy of 13 J in a 12-μsec pulse and an average specific output energy of ~10 J/liter. An analysis was made of the processes occurring in the Using cycle, the density of the excitation spectrum was estimated, and rates were obtained of the relaxation of the vibrational energy of the excited states and of the depopulation of the lower active state. The conditions under which a steady-state population inversion can exist in an I2 laser during continuous pumping were established. The maximum attainable efficiency was estimated to be ~1% for the pump source employed. The efficiency of conversion of the pump radiation energy in the I2 absorption band into laser radiation energy amounted to at least 6%. The quantum efficiency of lasing was not less than 11%. When the fluorescence was included, it was found that the quantum efficiency for the D' state of I₂ was several times higher.