Room-temperature operation of a multiwatt Tm : YAG laser pumped by a 1-mu m Nd : YAG laser

We present what is to our knowledge the first demonstration of a 4.7-W cw T m:YAG laser operating at room temperature by utilizing the extremely low 1. 064-mu m absorption in Tm:YAG. This proof-of-principle experiment clearly d emonstrates the possibility of using a pump absorption that is 2 orders of magnitude (similar to 0.0078 cm(-1)) less than that of the conventional pum p absorption (typically >1 cm(-1)). This Tm:YAG laser is pumped intracavity within a Nd:YAG laser for multiple-pass absorption. The maximum conversion efficiency of 2.02 mu m is 20%, with a slope efficiency of 35% with respec t to the absorbed 1.064-mu m power. (C) 2000 Optical Society of America.