Abstract

Yb-doped crystalline lasers have drawn significant attention during the last decade due to attractive properties such as an extremely low quantum defect, a wide emission spectrum and a simple energy level scheme. This has enabled powerful lasers in large multiple pump-pass thin-disk systems as well as in compact, end-pumped microchip systems. Among the more interesting host materials are GdCa₄O(BO₃)₃, GdCOB [1], and KGd(WO₄)₂, KGW [2], The potential advantage of Yb: GdCOB is the long upper laser level lifetime of 2.6 ms as well as the potential for self-frequency doubling. Yb:KGW on the other hand, shows emission and absorption cross-sections that are an order of magnitude higher than in GdCOB and most other rival host materials. The aim of the present work was to compare the performance of Yb: GdCOB and Yb:KGW under end-pumping by a non-fiber-coupled diode-bar.

© 2007 IEEE