Abstract

End pumping of solid-state lasers with high-power diode lasers has become a standard method to produce fundamental-mode laser radiation with high efficiency. The scaling of end-pumped, single-rod, fundamental-mode lasers to higher powers, however, very soon borders on principal limitations due to thermally induced beam distortions. A general relation between the minimum of the mode radius ω_min in the crystal rod and the range of the dioptric power ΔD of the thermal lens for which the resonator is stable, has been derived in ref. [1], For fundamental-mode operation in the whole stable region the effective pump spot has always to be smaller than the fundamental mode The possibility to enlarge the stability range with symmetric multirod Fabry-Perot resonators is discussed in ref [2]. We have found that a further enlargement of the stability range can be achieved with a ring cavity, where the stability region is given by the dotted area in fig. 2.

© 1996 IEEE