Gain and saturation parameter of a waveguide laser with distributed losses

An analysis is made of the problem of allowance for distributed losses αd in a gas-discharge waveguide laser when a determination is made of the gain 0 and of the saturation parameter Is from the output power P. Comparisons are made of the values of 0 and Is for a carbon monoxide waveguide laser, found experimentally by the method of calibrated losses allowing for and ignoring αd. A description is given of the method for the determination of 0 of a waveguide laser by a probe laser (which eliminates the influence of αd) and the results are given for the 1846.9 cm−1 line of the CO molecule. It is shown that when 0 and Is are calculated from the measured values of P, an allowance must be made for αd because otherwise the results are overestimated. Measurements are reported of the values of P obtained for CO waveguide lasers with capillaries of different lengths and a comparison is made between the experimental data and those calculated allowing for the values of αd.