Ho:YAG is the most important laser crystal used in medium wave infrared laser, which lasers at 2.10μm. The radiation wavelength of Ho3+ ions is near 2100nm, which is located in the human eye safe band and has a high transmittance in the atmosphere, and has important application prospect in the fields of remote sensing detection, laser ranging and laser radar, etc. Meanwhile, 2100nm locates in the absorption peak of water molecule, which is highly absorbed by human tissues. When Ho laser is used for medical surgery, its penetration depth in the human body is only a few tens of micrometers, and it has little heat damage to the surrounding tissues of the human body. Therefore, it is widely used in medical surgery and treatment.