Relaxation processes and influence of metastable states of metal atoms and ions on the lasing mechanism and energy characteristics of lasers

An investigation was made of relaxation processes of metastable states of Ba, Ba⁺, Ca⁺, Cu, Eu, Eu⁺, Mn, Pb, Sn, and Sr⁺ atoms and ions. It was found that metastable states are deexcited in collisions with electrons, identical ground-state atoms, buffer gas atoms, and with the walls. These processes were distinguished and measurements were made of their constants. It was established that under real conditions in lasers utilizing self-terminating transitions, metastable states relax within 10^–6–10^–8 sec and cannot be responsible for limiting the repetition frequency of the lasing pulses. An investigation was made of electron-beam-pumped Mn and Pb vapor lasers and it was shown that in this case the average output power may be two orders of magnitude higher than that for gas-discharge excitation. Lasers utilizing Ba, Eu, Eu⁺, Pb, and Sr⁺ were converted to quasi-cw or cw collisional lasing.