Gas mixture optimization for a CO2 CW laser system
Abstract
The operation of the carbon dioxide laser involves three different kinds of gas (carbon dioxide, nitrogen, and helium). The optimum gas mixture for two different laser tubes is determined experimentally. Laser tube A with an inner diameter of 10 mm and an electrode-toelectrode distance of 1.0 m operates at an optimum pressure of 10 torr. Laser tube B with an inner diameter of 7 mm and an electrode-to-electrode distance of 0.8 m operates at a higher pressure of 21 to 23 torr. However, 20 torr is sufficient to determine the optimum gas ratio. A mercury and oil differential manometer set-up is used to measure the partial pressures of the three gases — CO2: N2: He. For tube A the optimum gas ratio is 1:2:7 while the optimum gas ratio for tube B is also 1:2:7. Other aspects of the lasers may not be at optimum levels. Therefore, the value of the output power is of no importance but emphasis is placed on its behavior with varying gas mixtures.
