Zinc Selenide (CVD - ZnSe)

Download CVD - ZnSe Datasheet (PDF, 52 KB)

ZnSe is used as a material for production of optical elements (windows, lenses, prisms) for IR range including the passive laser optics elements. CVD - ZnSe is extremely uniform in structure; it has superior optical transmission with extremely low bulk losses from scatter and absorption. CVD - ZnSe is the first choice for high power laser windows and multispectral application with useful transmitting range of 0.5 - 19 mm. It offers excellent imaging characteristics, high resistance to thermal shock, and is stable in virtually all operating environments. This material is soft and non-hygroscopic.

Physical properties of ZnSe

Density @ 300 K, g/cm3 5.27
Melting point, K 1798
Thermal conductivity @ 298 K, J/(K x m x c) 18.0
Thermal expansion,

1/K

@ 273 K 7.1 x 10-6
@ 373 K 7.8 x 10-6
@ 473 K 8.3 x 10-6
Heat capacity @ 298 K, J/(g x K) 0.339
Hardness Knoop, with 50 g indenter, kg/mm2

120

Vickers, with 1 kg indenter, kg/mm2 112
Youngs modulus (E), Gpa 67.2

Bulk modulus (K), Gpa

40

Apparent elastic limit, Mpa

55.1

Fracture toughness MN m-1.5, Vickers, 100 g

0.5

Poisson's ratio

0.28

Solubility Insoluble in water
Resistivity, Ohm x cm 1012

Optical properties

Thermo-optic coefficient, (dn/dT)
@ 10.6 mm @ 298-358 K, 1/K
6.1 x 10 -5
Restrahlen peak, mm 45.7
Reflection loss @ 10.6 mm (2 surfaces), % 29.1
Reflection inhomogeneity (dn/n)
@ 0.633 mm, less than
3 x 10 -5

ZnSe refractive index vs wavelength

λ, μm
n
λ, μm
n
λ, μm
n
0.54
2.6754
3.00
2.4376
10.60
2.4028
0.58
2.6312
3.40
2.4356
11.40
2.3974
0.62
2.5994
3.80
2.4339
11.80
2.3945
0.66
2.5755
4.20
2.4324
12.20
2.3915
0.70
2.5568
4.60
2.4309
12.60
2.3883
0.74
2.5418
5.00
2.4295
13.00
2.3850
0.78
2.5295
5.40
2.4281
13.40
2.3816
0.82
2.5193
5.80
2.4266
13.80
2.3781
0.86
2.5107
6.20
2.4251
14.20
2.3744
0.90
2.5034
6.60
2.4235
14.60
2.3705
0.94
2.4971
7.00
2.4218
15.00
2.3665
0.98
2.4916
7.40
2.4201
15.40
2.3623
1.00
2.4892
7.80
2.4183
15.80
2.3579
1.40
2.4609
8.20
2.4163
16.20
2.3534
1.50
2.4560
8.60
2.4143
16.60
2.3487
1.80
2.4496
9.00
2.4122
17.00
2.3438
2.00
2.4460
9.40
2.4100
17.40
2.3387
2.20
2.4437
9.80
2.4077
17.80
2.3333
2.60
2.4401
10.20
2.4053
18.20
2.3278

Depending on application we use two grades of CVD - ZnSe with different optical properties. There is no difference in transmission at 8 mm and above (see Fig.1).

Transmission spectrum

  Fig. 1 Transmission spectrum of CVD - ZnSe window thickness of 10 mm.

  G 1 G 2
Absorption index
@ 10.6 mm, less than, 1/cm
(5 - 8) x 10 - 4 1 x 10 -3
Damage threshold, not less than, kW/cm2 2 - 3 -

CVD - ZnSe blanks are available in diameters 2 - 200 mm with thickness to 15 - 20 mm.