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

We present what is to our knowledge the first demonstration of a 4.7-W cw Tm: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 demonstrates 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 pump 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 respect to the absorbed 1.064-mu m power. (C) 2000 Optical Society of America.