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Nonlinear
Crystals
Introduce
Nonlinear
Crystals
Laser
Crystals
AO
& EO Crystals
Optical
Crystals
YAG
YVO4
¦Á-BBO
Quartz
Sapphire
(Al2O3)
Spinel
(MgAl2O4)
Calcite
(CaCO3)
Magnesium
Fluoride (MgF2)
Calcium
Fluoride (CaF2)
Lithium
Fluoride (LiF)
Barium
Fluoride (BaF2)
Zinc Sulphide
(ZnS)
Zinc
Selenide (ZnSe)
Gallium
Arsenide (GaAs)
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Zinc
Sulphide (ZnS)
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Used
for IR windows and lenses in the thermal band (8 to 14 microns)
where maximum transmission and lowest absorption is required.
Also selected for use where visible alignment is an advantage.
Zinc Sulphide is produced by synthesis from zinc vapour and
H2S gas, forming as sheets on graphite susceptors. It is microcrystalline
in structure, the grain size being controlled to produce maximum
strength. Multispectral grade is then Hot isostatically pressed
(HIP) to improve the mid IR transmission and produce the visibly
clear form. Polycrystal ZnS is available.
|
| Specifications
of ZnS |
| Transmission
Range |
0.37 to 13.5¦Ìm |
|
Refractive
Index |
2.20084
at 10m¦Ìm |
|
Reflection
Loss |
0.0006 cm-1 at 3.8¦Ìm |
|
Restrahlen
Peak |
30.5¦Ìm |
|
dn/dT |
+38.7 x 10-6/¡ãC at 3.39¦Ìm |
|
Density
|
4.09g/cm3 |
|
Melting
Point |
1827¡ãC (dissociates about 700¡ãC) |
|
Thermal
Conductivity |
27.2 W/(m K) at 298K |
|
Thermal Expansion |
6.5 x 10-6/ ¡ãC at 273K |
| Hardness |
Knoop 160 with 50g indenter |
|
Specific Heat Capacity |
515
J ¡¤ kg-1 ¡¤ K-1 |
|
Dielectric Constant |
8 |
| Young's
Modulus (E) |
74.5 GPa |
| Apparent
Elastic Limit |
68.9 MPa (10,000psi) |
| Poisson
Ratio |
0.28 |
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