Passive switching of the Q factor of a CO2 laser by a saturable filter containing OsO4 vapor

An experimental investigation was made of the passive switching of the Q factor of a CO₂–N₂–He laser by the saturation of the resonant absorption in OsO₄ vapor. Passive switching of the Q factor was observed, in a nonselective resonator, for the P(24) line of the 00⁰1–10⁰0 band of CO₂. The introduction of an NaCl prism as a dispersing element resulted in the switching of the Q factor corresponding to the P(4)–P(26) lines and the R(4)–R(28) lines of the same CO₂ band. The duration of the output pulses was 1–2 μsec. The pulse repetition frequency was 20–50 kHz. The pulse output power was 10–15 times greater than the power of a continuous wave generated in the absence of an absorber. An investigation was made of the influence on the Q-switching conditions of the parameters of the active medium (the pressures of the components and the discharge current) and of the pressure in the absorber cuvette.