Infrared laser action in Yb3+:YCOB (Yb3+:YCa4O(BO3)(3)) is reported fo
r the first time. Maximum output powers of similar to 300 mW with a sl
ope efficiency of 35.8% have been obtained. The observation of self-fr
equency doubling in this material is also reported. (C) 1998 Elsevier
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