Design considerations and scaling laws for high power convective cooled CWCO2 lasers

Various criteria for designing high power convective cooled CO2 lasers have been discussed. Considering the saturation intensity, optical damage thres hold of the optical resonator components and the small-signal gain, the sca ling laws for designing high power CW CO2 lasers have been established. In transverse flow CO2 lasers having discharge of square cross-section, the di scharge length L and its width W for a specific laser power P (Watt) and ga s flow velocity V (cm/s) can be given by L = 1.4 x 10(4)P(1)/V-2(-1) ems an d W = 0.04P(1/2) cms. The optimum transmitivity of the output coupler is found to be almost const ant (about 60%), independent of the small signal gain and laser power. In f ast axial flow CO2 lasers the gas flow should be divided into several disch arge tubes to maintain the flow velocity within sonic limit. The discharge length in this type of laser does not depend explicitly on the laser power, instead it depends on the input power density in the discharge and the gas flow velocity. Various considerations for ensuring better laser beam quali ty are also discussed.