High-Power 2.09µm Tm,Ho:YAG Lasers: A Review of 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 resulted in an average output power of 7.6W due to detrimental up-conversion losses [13]. Since then, there have been no reports of achieving over 10W output power with Tm,Ho:YAG crystal. Nevertheless, in 2014, Zhang Chao et al. employed two side-pumped laser modules with Tm:YAG and Tm,Ho:YAG in the same cavity, which generated a continuous wave output power of 37W at 2.1µm [14]. This is the highest 2.09µm output power achieved to date with co-doped Tm,Ho:YAG. However, the optical-to-optical efficiency for this system is only 3.1%.