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. Ho laser can also be used as pump source, through the non-linear effect of crystal (such as ZGP crystal), infrared laser with wavelength of 3 ~ 5 mm can be realized.
Physical and Chemical Properties
| Crystal Structure | Cubic |
| Lattice Constants | 12.01Å |
| Density | 4.56g/cm3 |
| Melting Point | 1970°C |
| Thermal Conductivity | 14W/m/K, 20°C; 10.5W/m/K, 100°C |
| Thermal Shock Resistance | 790W/m |
| Thermal Optical Coefficient(dn/dT) | 7.3×10-6/ K |
| Thermal Expansion /（10-6·K-1@25°C ） | [100]:8.2×10-6/K@ 0~250℃; [110]:7.7×10-6/K@0~250℃; |
| [111]: 7.8×10-6/K@0~250℃ | |
| Hardness (Mohs) | 8.5 |
| Young`s Modulus /GPa | 3.17×104Kg/mm2 |
| Shear Modulus /Gpa | 310GPa |
| Extinction Ratio | >28dB |
| Specific Heat | 0.59J/g.cm3@0-20℃ |
| Solubility | Insoluble in water, slightly soluble in ordinary acids |
| Poisson Ratio | 0.3 |
Optical and Spectral Properties
| Laser Transition | 5I7→5I8 |
| Laser Wavelength | 2.05μm |
| Effective Stimulated Absorption Cross Section | 1.09×10-20cm2 |
| Effectively Stimulated Emission Cross Section | 1.14×10-20cm2 |
| Pump Wavelength | 1908 nm |
| Laser Wavelength | 2090 nm |
| Fluorescence Lifetime | 7 ms |
| quantum Efficiency | 1 |
| Refractive Index @1.030 μm | 1.82 |
| Upper Conversion Loss Factor | 1.8, 2.6, 5.3×10-18cm3/s |
Absorption and Emission Spectrum
Material and Specifications
| Materials | Ho: YAG |
| Concentration Tolerance (atm%) | 0.2% ~3%(as per customers request) |
| Orientation | <111>crystalline direction |
| Parallelism | <10” |
| Perpendicularity | <5” |
| Surface Quality | 10/5 Scratch/dig per MIL-O-1380A |
| Wavefront Distortion | λ/8per inch @633nm |
| Surface Flatness | λ/10@ 633 nm |
| Clear Aperture | >90 |
| Thickness/Diameter Tolerance | Rods with diameter:(+0、-0.05)mm,( ±0.5) mm |
High laser gain
Safe for eyes and good atmosphere transmission
High-energy storage capability
Low quantum defect
Long fluorescence life
Large emission cross section
High slope efficiency
Low up-conversion loss and re-absorption loss
Medical Applications
Optical communication
Remote sensing and radar
Laser chemistry
Laser spectrum
Material processing,
Laser ranging