High-Power 2.09μm Tm,Ho:YAG Laser: A Review of Current Performance and Efficiency

In 1993, Bowman conducted a study on the performance of a side-pumped Tm,Ho:YAG laser with varying dopant concentrations of the crystal. However, the study only obtained an average output power of 7.6W [13] due to detrimental up-conversion losses. Since then, there have been no reports of over 10W output power with Tm,Ho:YAG crystal. In 2014, Zhang Chao et al. employed two side-pumped laser modules with Tm:YAG and Tm,Ho:YAG in the same cavity, generating a cw output power of 37W at 2.1μm [14]. This is the highest 2.09μm output power achieved so far with co-doped Tm,Ho:YAG. However, the optical-to-optical efficiency for this system is only 3.1%.