22 May 2019 Description
Cr: ZnSe laser crystal has the advantages of normally no excited state absorption and upper level conversion, an extremely broad absorption band and large emission cross-section, superb fluorescence quantum efficiency at room temperature and extra broad emission width as well as good chemical and mechanical properties, which make it become an excellent source of efficient and powerful tunable mid infrared laser. Because of mid infrared wavelength band is the window of atmosphere, the Cr: ZnSe laser crystal has important application prospect in the field of photo-communication, pollution gas detection, industrial combustion product test and so on.
Parameter
Material and Specifications
| Crystal structure |
Cubic |
| Poisson Ration |
0.28 |
| Thickness/Diameter Tolerance |
±0.05mm |
| Orientation Tolerence |
< 0.5° |
| Surface Flatness |
<λ/8@632nm |
| Wavefront Distortion |
<λ/4@632nm |
| Surface Quality |
10-5(MIL-O-13830A) |
| Parallel |
30〞 |
| Perpendicular |
15ˊ |
| Clear Aperture |
>90% |
| Chamfer |
<0.2×45° |
| Melting Point |
1520 ºC |
Physical and Chemical Properties
| Thermal Expansion Coeff. @20ºC |
1.5×10-6/ºC |
| Thermal Conductivity Coeff. @20ºC |
14 W/m/ºK |
| Specific Heat |
0.79 J/g K |
| Density |
5.27 g/cm³ |
| Durability Knoop Hardness |
112 kgf/mm² |
| Mohs Hardness |
8.5 |
| Young‘s Modulus |
67 GPa |
| Modulus of Rupture |
55 MPa |
| Orientation |
or |
Optical and Spectral Properties
| Laser Wavelengths |
2150 – 2600 nm |
| Emission Linewidth |
|
| Emission Cross-section (@1064nm) |
9×10-19 cm² |
| Intrinsic Loss @1064nm |
-1 |
| Refractive Index (n) @ 1650nm |
2.455 |
| Thermal Optical Coeff. (dn/dT) @nm |
61×10-6/ºC |
Absorption and Emission Spectrum
 
Feature
-
Broad tunability (lasing from 2.1-3.1 μm)
-
Broad absorption bands
-
Large gain cross section (σemission ~ 9 × 10-19 cm2)
-
Minimal problem of excited state absorption (no spin-allowed excited state transitions from the upper laser level)
-
High thermal conductivity − better than YAG (18 W/m·K in ZnSe versus 13 W/m·K in YAG)
-
High IR (0.6-20 μm) transparency
Application
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