Comparative analysis of single-mode laser resonators

A comparative analysis is made of generalized confocal resonators and of unstable resonators with radiation coupling out by diffraction on the finite aperture of the exit mirror or by transmission through this mirror. It is shown that generalized confocal resonators make it possible to increase considerably (by a factor of 7) the output power of a single-mode laser compared with a traditional confocal resonator, but when used in pulsed lasers the mirrors have to be of high optical strength because radiation is focused on the mirrors. It is suggested that a telescopic resonator with an exit semitransparent mirror of finite aperture can be used in pulsed lasers: this should make it possible to increase the fraction of the power in the central maximum of the far-field pattern from 30 to 80% in the range of low telescope magnifications M≤2.