Laser & optical crystals0 pages
CVD ZnSe (CVD Zinc Selenide) - Main Properties
Zinc selenide is a clear yellow polycrystalline material with a grain size of approximately 70µm,
transmitting in the range 0.5-15µm. 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 10.6µm. 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 antireflectance coatings do serve to protect ZnSe.
Zinc Selenide is a relatively soft material and
scratches rather easily. It requires an antireflection 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 @ 10.6µm
Temp. Change of Refractive Index @ 10.6µm
Refractive Index Non-homogeneity @ 632.8nm
Thermal Properties
Thermal Conductivity
Specific Heat
Linear Expansion Coefficient @ 20°C
0.0005/cm
61x10-6/°C
<6X10-6
0.18W/cm/°C
0.356J/g/°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
(µm)
Index
0,54
2,68
1,8
2,45
0,58
2,63
2,2
0,62
2,60
0,66
Wavelength
Wavelength
Index
(µm)
(µm)
Index
Wavelength
(µm)
Index
7,4
2,42
13.0
2,39
2,44
7,8
2,42
13,4
2,38
2,6
2,44
8,2
2,42
13,8
2,38
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
http://www.SintecOptronics.com http://www.SintecOptronics.com.sg
1
"