Simplified method for calculating the unstable optical resonators of flow-type gas lasers

A novel simplified method for calculating unstable optical resonators is proposed which yields satisfactory results in a wide range of magnification values with a greater than two-order-of-magnitude reduction in computational time as compared with the 'exact' method. The proposed approach is based on the radiation transfer equation in the geometrical-optics approximation and one-dimensional equations of gas dynamics and kinetics. Results are presented for various types of resonators, including single- and double-pass telescopic.