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Silicon (Si) Windows

  • Low density and light weight
  • Maximum diameter 300mm
  • Both Czochralski Pulling grown (CZ) and Float-Zone (FZ) processed Silicon available
  • Transmitting range 1.2μm to 14.0μm
  • Fit for both MWIR (3-5μm) and LWIR (8-12μm) applications
  • Coating options: DLC coating, AR coating
  • Low cost
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Specifications:

Materials Silicon crystals (CZ or FZ)  Diameter Range ~ 300mm
Aperture >90% Dimension Tolerance +0.0/-0.2mm
Thickness Tolerance +/-0.1mm Surface Quality 60/40 S/D
Parallelism 1 arc minute Chamfer 0.3-0.5mmx45degree
Coating AR/AR or DLC/AR

 

Basic Properties:

Transmission Range 1.2 to 15 μm (1) Refractive Index 3.4223 @ 5 μm (1) (2)
Reflection Loss 46.2% at 5 μm (2 surfaces) Absorption Coefficient 0.01 cm-1 at 3 μm
Reststrahlen Peak n/a dn/dT 160 x 10-6 /°C (3)
dn/dμ = 0 10.4 μm Density 2.33 g/cc
Melting Point 1420 °C Thermal Conductivity 163.3 W m-1 K-1 at 273 K
Thermal Expansion 2.6 x 10-6 / at 20°C Hardness Knoop 1150
Specific Heat Capacity 703 J Kg-1 K-1 Dielectric Constant 13 at 10 GHz
Youngs Modulus (E) 131 GPa (4) Shear Modulus (G) 79.9 GPa (4)
Bulk Modulus (K) 102 GPa Elastic Coefficients C11=167; C12=65; C44=80 (4)
Apparent Elastic Limit 124.1MPa (18000 psi) Poisson Ratio 0.266 (4)
Solubility Insoluble in Water Molecular Weight 28.09
Class/Structure Cubic diamond, Fd3m

Silicon (Si) Windows manufactured from optical grade silicon are popular for the 1.2 - 14μm spectral region due to their low cost and low density. Due to its low density (half that of germanium or zinc Selenide), silicon is ideal for weight sensitive applications, especially those in the MWIR thermal imaging 3 - 5μm region. Density is 2.329 g/cm3 and Knoop Hardness is 1150, making it harder and less brittle than germanium.

Silicon could be grown by Czochralski Pulling Technique (CZ) and the Float-Zone (FZ) process, Silicon by CZ has some oxygen which lead to absorption band at 9 microns, both CZ and FZ has good transmission at 3-5 miro MWIR band. But for LWIR (8-12 microns) band applications, the FZ made silicon should be choosen. There is some absorption above 7 micron for silicon materials, however, when you decrease the thickness of the windows, such as less than 1.0mm, you still could get high transmission about 90% at LWIR (8-12 micron) scpectal band after coating. In addition to its low cost, silicon windows has become a excellent choice for sensors applications. 

Hangzhou Shalom EO offers the both Czochralski (CZ) grown and Float-Zone (FZ) made silicon windows, operate at MWIR and LWIR bands with DLC or AR coating, largest diameter of 300mm is available. 

Silicon could be grown by Czochralski Pulling Technique (CZ) and the Float-Zone (FZ) process, Silicon by CZ has some oxygen which lead to absorption band at 9 microns, both CZ and FZ has good transmission at 3-5 miro MWIR band. But for LWIR (8-12 microns) band applications, the FZ made silicon should be choosen. There is some absorption above 7 micron for silicon materials, however, when you decrease the thickness of the windows, such as less than 1.0mm, you still could get high transmission about 90% at LWIR (8-12 micron) scpectal band after coating. In addition to its low cost, silicon windows has become a excellent choice for sensors applications.


1. Transmission curve of the Czochralski (CZ)grown Silicon and Float-Zone (FZ) made Silicon (no coating)

 


2. Transmission curve of the Silicon windows with AR/AR coating at 3-5μm


 

Silicon Lenses

Silicon Lenses

  • Low density and light weight
  • Maximum diameter 300mm
  • Transmitting range 1.2μm to 7.0μm
  • Coating options: DLC coating, AR coating
  • Low cost
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