Zinc
selenide is a clear yellow polycrystalline material with a grain size of
approximately 70�m, transmitting in the range 0.5-15�m. It is
essentially free of extrinsic impurity absorptions, providing extremely
low bulk losses from scatter. Zinc Selenide, produced by the method of
chemical vapour deposition, is the preferred material for optics used in
high power CO2 laser systems due to its low absorption at
10.6�m. However it is also a popular choice in systems operating at
various bands within its wide transmission range. ZnSe has a high
resistance to thermal shock making it the best material for high power
CO2 laser systems. ZnSe however is only 2/3 the hardness of
ZnS multi-specral grade but the harder anti-reflectance coatings do
serve to protect ZnSe. Zinc Selenide is a relatively soft material and
scratches rather easily. It requires an anti- reflection coating due to
its high refractive index if high transmission is required. ZnSe has a
rather low dispersion across its useful transmission range. For high
power applications, it is critical that the material bulk absorption and
internal defect structure be carefully controlled, that minimum-damage
polishing technology be employed, and the highest quality optical thin
film coatings are used.
Optical
Properties
Bulk Absorption Coefficient @ 10.6�m |
0.0005/cm |
Temp. Change of Refractive Index @ 10.6�m |
61x10-6/�C |
Refractive Index Non-homogeneity @ 632.8nm |
<6X10-6 |
Thermal
Properties
Thermal Conductivity |
0.18W/cm/�C |
Specific Heat |
0.356J/g/�C |
Linear Expansion Coefficient @ 20�C |
7.57x10-6/�C |
Mechanical
Properties
Young's Modulus |
6.85X1011 dyne/cm2 |
Rupture Modulus |
5.7X108 dyne/cm2 |
Knoop Hardness |
110-130Kg/mm2 |
Density |
5.27g/cm3 |
Poisson's Ratio |
0.28 |
Refractive Index of CVD ZnSe:
Wavelength
(�m) |
Index |
Wavelength
(�m) |
Index |
Wavelength
(�m) |
Index |
Wavelength
(�m) |
Index |
0,54 |
2,68 |
1,8 |
2,45 |
7,4 |
2,42 |
13.0 |
2,39 |
0,58 |
2,63 |
2,2 |
2,44 |
7,8 |
2,42 |
13,4 |
2,38 |
0,62 |
2,60 |
2,6 |
2,44 |
8,2 |
2,42 |
13,8 |
2,38 |
0,66 |
2,58 |
3.0 |
2,44 |
8,6 |
2,41 |
14,2 |
2,37 |
0,70 |
2,56 |
3,4 |
2,44 |
9.0 |
2,41 |
14,6 |
2,37 |
0,74 |
2,54 |
3,8 |
2,43 |
9,40 |
2,41 |
15.0 |
2,37 |
0,78 |
2,53 |
4,2 |
2,43 |
9,80 |
2,41 |
15,4 |
2,36 |
0,82 |
2,52 |
4,6 |
2,43 |
10,2 |
2,41 |
15,8 |
2,36 |
0,86 |
2,51 |
5.0 |
2,43 |
10,6 |
2,40 |
16,2 |
2,35 |
0,90 |
2,50 |
5,4 |
2,43 |
11.0 |
2,40 |
16,6 |
2,35 |
0,94 |
2,50 |
5,8 |
2,43 |
11,4 |
2,40 |
17.0 |
2,34 |
0,98 |
2,49 |
6,2 |
2,43 |
11,8 |
2,39 |
17,4 |
2,34 |
1.0 |
2,49 |
6,6 |
2,42 |
12,2 |
2,39 |
17,8 |
2,33 |
1,4 |
2,46 |
7.0 |
2,42 |
12,6 |
2,39 |
18,2 |
2,33 |
Zinc Serenade
Transmission Graph
|