Abstract

In a laser resonator operating with many transverse modes, the divergence of the emerging beam is relatively high, resulting in a high M² value. To reduce the divergence, it is best to reduce the number of the modes, preferably to a single mode. Typically, this is achieved by introducing an aperture inside the cavity, so the laser resonator will operate with a single TEM₀₀ mode. Unfortunately, this results in a significant reduction of the output power, since only a small volume of the gain medium is exploited.

© 1998 IEEE