Highly efficient repetitively pulsed electric-discharge industrial CO2 laser

The results of investigations aimed at the development of a repetitively pulsed CO₂ laser with an active medium volume of 1000 cm³ pumped by a combined discharge are generalised. It is shown that, at pump pulse durations of 200–500 μs the optimal characteristics are achieved at active-medium pressures of 60—100 Torr. In this case, the laser efficiency at the initial stage of its operation can reach 22% and; if the energy dissipated in the region of the cathode potential drop is neglected, the efficiency is 28%. After emission of 3×10⁵ pulses, the laser efficiency falls to 12%. It has been found that adding CO with a relative concentration [CO]/[CO₂] ~0.75 increases the input and output power by almost 50%. The lasing efficiency is then 10%–12%, and the service life of the laser is by more than 10⁶ pulses with a power decrease of no more than 10%. Adding hydrogen up to a concentration [H₂]/[CO₂] ~10 leads to an increase in the energy supplied to the gas due to a decrease in the rate of ionisation processes. However, the optimal ratio is [H₂]/[CO₂] ~ 1, at which the output power increases by 15%. In a long-term operating mode, the laser power is 1 kW at a peak power of 10 kW and an efficiency of 12%.