Abstract

With rising power in cw and pulsed operation erbium 3-μm lasers work their way into a variety of applications in surgery. Despite the unfavorable ratio of upper-level to lower-level lifetime cw laser operation is achieved in fluoride host materials solely due to the small branching ratio on the laser transition [1]. CW output powers exceed 1 W in LiYF₄ [2] and 150 mW in a ZBLAN fiber [3]. Owing to geometry and erbium concentration the population mechanisms are different in crystals and fibers [4]. These mechanisms determine different concepts of energy recycling in the mentioned materials.

© 1996 IEEE