Ho:Cr:Tm:YAG is a high efficient laser material which lases at 2.1 µm. It has wide applications in surgery, dentistry, atmospheric testing, etc. High spectral overlap of pump radiation (lamp or diode) with the Cr3+ and Tm3+ absorption bands, and a highly efficient conversion from the absorption bands into the 5I7 -> 5I8 Ho3+ emission band, enables 2 micron laser architectures with high quantum efficiency.
Ho:Cr:Tm:YAG Crystal Features:
- High slope efficiency
- Pumped by flash lamp or diode
- Operates well at room temperature
- Operates in a relatively eye-safe wavelength range
Ho:Cr:Tm:YAG Crystal Physical Properties:
Crystal Structure |
Cubic |
Lattice Parameters |
12.01 Å |
Melting Point |
1970 °C |
Moh Hardness |
8.5 |
Density |
4.56±0.04g/cm3 |
Specific Heat (0-20) |
0.59J/g.cm 3 |
Modulus of Elasticity |
310GPa |
Young's Modulus |
3.17 x 104 Kg/mm2 |
Poisson Ratio |
0.3(est.) |
Tensile Strength |
0.13~0.26GPa |
Thermal Expansion Coefficient |
[100]Direction:8.2x10-6 / °C (0~250 °C ) [110]Direction:7.7x10-6 / °C (0~250 °C ) [111]Direction:7.8x10-6 / °C (0~250 °C ) |
Thermal Conductivity |
14W/m/K(@20 °C ) 10.5W/m/K(@100 °C ) |
Thermal Optical Coefficient (dn/dT) |
7.3×10-6 / °C |
Thermal Shock Resistance |
790W/m |
Ho:Cr:Tm:YAG Crystal Optical Properties:
Laser Transition |
5I7 -> 5I8 |
Laser Wavelength |
2097nm |
Photon Energy |
9.55×10-20J |
Emission Cross Section |
7×10-21 cm2 |
Fluorescence Lifetime |
8.5 ms |
Absorption Linewidth |
4 nm |
Diode Pump Band |
781 nm |
Major Pump Bands |
400~800 nm |
Index of Refraction |
1.80 @2080nm |
Sellemeier equation (λ in um) |
n2=2.08745+1.2081λ2/(λ2-0.02119)+17.2049λ2/(λ2-1404.45) |
Ho:Cr:Tm:YAG Standard Product Specifications:
Dopant concentration |
Ho: ~ 0.35 at%, Tm: ~ 5.8 at%, Cr:~1.5at% |
Orientation |
<111> or <100> crystalline within 5° |
Wavefront distortion |
λ /8 @ 633 nm |
Extinction Ratio |
>25dB |
Rod Sizes |
Diameter:3~6mm, Length:50~120 mm |
Dimension Tolerances |
Diameter: ±0.025 mm, Length: ±0.5 mm |
Surface quality |
10/5 Scratch / Dig per MIL-O-1380A |
Parallelism |
< 10 arc seconds |
Perpendicularity |
< 5 arc minutes |
Flatness |
< λ /10 @ 633 nm |
Chamfer |
<0.1 mm @ 45deg. |
Barrel Finish |
Ground Finish: 400# Grit |
AR Coating Reflectivity |
< 0.25% |