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Zinc Selenide (ZnSe) Crystal
ZnSe is widely used for IR components, windows and lenses and spectroscopic ATR prisms. Zinc Selenide is one of the choice for CO2 laser optics operating at 10.6 microns.
Refractive Index : 2.4028 at 10.6 µm
Reflection Loss : 29.1% at 10.6 µm (2 surfaces)
Absorption Coefficient : 0.0005 cm-1 at 10.6 µm
Reststrahlen Peak : 45.7 µm
dn/dT : +61 x 10E-6/°C at 10.6 µm at 298K
dn/dµ = 0 : 5.5 µm
Density : 5.27 g/cm³
Melting Point : 1525°C (see notes below)
Thermal Conductivity : 18 W m-1 K-1 at 298K
Thermal Expansion : 7.1 x 10E-6 /°C at 273K
Hardness : Knoop 120 with 50g indenter
Specific Heat Capacity : 339 J Kg-1 K-1
Youngs Modulus (E) : 67.2 GPa
Bulk Modulus (K) : 40 GPa
Apparent Elastic Limit : 55.1 MPa (8000 psi)
Poisson Ratio : 0.28
Solubility : 0.001g/100g water
Molecular Weight : 144.33
Class/Structure : HIP polycrystalline cubic, ZnS, F43m
Typical application: Thermal imaging, FLIR.
Products manufactured: Lenses, Aspheric Lenses, Binary (diffractive) Lenses, Windows, Optical Beamsplitters and Optical Filters, Prism.
Surface Finish: Typical 40-20 or 60-40 scratch-dig. Diamond Turned 150
Angstroms rms or better.
SurfaceFlatness: Range from 1/2 wave to 2 waves @633nm depending on the
system performance requirements.
AR coating: BBAR for 0.8 to 2.5µm, 3 to 5µm, 1 to 5µm,
8 to 12µm, and the 3 to 12µm spectral regions and single wavelength
coating AR at 10.6µm. Many other specialized wavelength bands are
possible within the 0.6 to 16µm range.
Product Notes:
Zinc Selenide is produced by synthesis from Zinc vapour and H2Se gas,
forming as sheets on Graphite susceptors. Zinc Selenide is microcrystalline
in structure, the grain size being controlled to produce maximum strength.
Single crystal ZnSe is available, but is not common but has been reported
as having lower absorption and thus more effective for CO2 optics.
Zinc Selenide oxidizes significantly at 300°C, exhibits plastic deformation at about 500°C and dissociates about 700°C. For safety, Zinc Selenide windows should not be used above 250°C in normal atmosphere.
Applications:
IR optical components, which operate as elements of high power CO2-lasers (windows, lenses, prisms, beamspliters etc.) The different coatings on the elements are available.
ZnSe oriented single crystals rods as IR electrooptical modulators with max dimensions 5 x 10 x 45 mm3, any crystallographic orientation, resistivity >1010 Ohm x cm.
ZnSe oriented cubics with dimensions 10 x 10 x 10 mm3, high resistivity (>1010 Ohm x cm).
ZnSe substrates to fabricate heterojurunctions with GaAs film (blue light emission diodes and lasers) plates 10 x 10 mm2, 10 x 20 mm2, 10 x 30 mm2 or any other form with thickness of 1 - 2 mm, (111) or (100) orientation, high resistivity (>1010 Ohm x cm), free of twins, EPD is 104/ cm2.
CdS oriented plates with low (<10-1 Ohm x cm) and high resistivity (>108 Ohm x cm)
Zinc Sulphide ZnS Crystal
ZnS Multispectral (water-clear) is used for IR windows and lenses in the thermal band (8 to 14 µm) where maximum transmission and lowest absorption is required. ZnS is also selected for use where visible alignment is an advantage.
ZnS Crystal Properties
Refractive Index : 2.20084 at 10 µm
Reflection Loss : 24.7% at 10 µm (2 surfaces)
Absorption Coefficient : 0.0006 cm-1 at 3.8 µm
Reststrahlen Peak : 30.5 µm
dn/dT : +38.7 x 10E-6 /°C at 3.39 µm
Density : 4.09 g/cm³
Melting Point : 1827°C
Thermal Conductivity : 27.2 W m-1 K-1 at 298K
Thermal Expansion : 6.5 x 10-6 /°C at 273K
Hardness : Knoop 160 with 50g indenter
Specific Heat Capacity : 515 J Kg-1 K-1
Dielectric Constant : 88
Youngs Modulus (E) : 74.5 GPa
Apparent Elastic Limit : 68.9 MPa (10,000 psi)
Poisson Ratio : 0.28
Solubility : 65 x 10E-6 g/100g water
Molecular Weight : 97.43
Class/Structure : HIP polycrystalline cubic, ZnS, F42m
Due to its good transmission in the VIS and IR, Cleartran ZnS is an ideal choice for systems with a visible cameras,and and various IR detectors or IR cameras.
Typical application: Visible imaging, thermal imaging, FLIR, astronomy
Products manufactured: Lenses,aspheric lenses ,binary(diffractive) lenses,windows,beamsplitters and optical filters and prisms
Surface Finish: Typical 40-20 or 60-40 scratch-dig. Diamond Turned 100
Angstroms rms or better.
Surface Flatness: Range from 1/2 wave to 2 waves @633nm depending on the
system performance requirements.
AR coating: BBAR for 0.8 to 2.5µm, 3 to 5µm, 1 to 5µm,
8 to 12µm, and the 3 to 12µm spectral regions. Other specialized
bands are possible from 0.4 to 12 µm.
Product Notes:
Zinc Sulphide oxidizes significantly at 300°C, exhibits plastic deformation
at about 500°C and dissociates about 700°C. For safety, Zinc Sulphide
windows should not be used above 250°C in normal atmosphere.