Numerical three-dimensional modelling of a cw CO2 amplifier with transverse pumping of the active medium

A three-dimensional mathematical model of a cw CO₂ amplifier with transverse flow is constructed. The model takes into account the refraction of radiation and the saturation of the active-medium gain. Numerical methods with higher precision are proposed for approximate integration of a parabolic equation describing the propagation of radiation and for determination of two-dimensional intensity distributions in the far-field zone. The cases of amplification of beams of various forms are considered for certain multipass amplifier configurations with electric-discharge excitation. The dependences of the angular divergence of the output radiation on the length of the active medium are obtained.