Calculation of the efficiency of a laser exhibiting large radiation losses

The results are given of a theoretical calculation of the energy characteristics of a laser with an unstable telescopic resonator. These results show that when the parameters of the resonator are optimal with respect to the efficiency, one can usually employ the standard equations of probability theory derived for a planar resonator. It is shown that these equations are inapplicable when the passive losses are considerable or when the laser threshold is exceeded appreciably. A simple method is suggested for estimating the efficiency of a laser in such cases.