|
Introduction
Ho:Cr:Tm:YAG is a high
efficiency laser material which lasers at 2.1µm. It has
wide applications in medical, military and meteorology fields.
 May be flash lamp or diode pumped
Very high slope efficiency
Operates well at room temperature
Operates in a relatively eye-safe wavelength range High
efficiency
Basic Properties:
| Crystal Structure |
Cubic |
| Lattice Parameters |
12.01 Å |
| Melting Point |
1970 °C |
| Moh Hardness |
8.5 |
| Density |
4.56±0.04g/cm 3 |
| Specific Heat (0-20) |
0.59J/g.cm 3 |
| Modulus of Elasticity |
310GPa |
| Young's Modulus |
3.17X10 4 Kg/mm 2 |
| 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 |
The Sellmeier equations (l in µm for YAG):
n ^2 = 2.08745 + 1.2081 l ^2
/(l^ 2 - 0.02119 )+ 17.2049 l ^2 /(l ^2 -
1404.45 )
Optical and Spectral Properties
| Doping(atm%): |
Ho: ~ 0.35 at%, Tm: ~
5.8 at%,Cr:~1.5at% |
| Laser Transition |
5 I 7 - 5 I 8 |
| Laser Wavelength |
2.097 µm |
| Photon Energy |
9.55 x 10 -20 J |
| Emission Cross Section |
7 x 10 -21 cm 2 |
| 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 @2.08 µm |
Ho:Cr:Tm:YAG's Specifications:
| Orientation: |
<111> or <100]> crystalline
within 5° |
| Wavefront distortion : |
l /8 per
inch @ 633 nm |
| Extinction Ratio: |
>25dB |
| Dimension Tolerances |
Rods with diameter: ±0.025 mm ,
Length: ±0.5 mm |
| Surface quality: |
10/5 Scratch / Digper MIL-O-1380A
|
| Parallelism: |
< 10 arc seconds |
| Perpendicularity: |
< 5 arc minutes |
| Flatness: |
< l /10
@ 633 nm |
| chamfer: |
<0.1 mm @ 45deg. |
| Barrel Finish: |
50-80 micro-inch (RMS) , |
| AR Coating Reflectivity |
<0.25% |
|
Barrel
Finish:
|
50-80
micro-inch (RMS) , |
Note: The other specification and dimension is available
too |
Laser Crystals