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CaF2 Lenses

  • Maximum diameter 200mm
  • Transmitting range 0.18μm to 8.0μm
  • Fit for MWIR (3-5μm) thermal imagine applications
  • Covers UV to IR wavelength spectra
Curves All Inquire Us  

Specifications:

Materials  CaF2 crystals Diameter Range ~200mm
Diameter Tolerance  +0.0/-0.2mm Thickness Tolerance +/-0.1mm
Surface Quality 60/40 S/D  Frings (N) 3
Irregularity (delta N) 1 Centration 3'
Chamfer 0.1-0.3mmx45 degree Coatings AR/AR@3-5micro
 

Physical and Optical Properties:

Transmission Range 0.13 to 10 μm Refractive Index 1.39908 at 5 μm (1) (2)
Reflection Loss 5.4% at 5 μm Absorption Coefficient 7.8 x 10-4 cm-1 @ 2.7 μm
Reststrahlen Peak 35 μm dn/dT -10.6 x 10-6/°C (3)
dn/dμ = 0 1.7 μm Density 3.18 g/cc
Melting Point 1360°C Thermal Conductivity 18.85 x 10-6/°C (5)(6)
Hardness Knoop 158.3 (100) with 500g indenter Specific Heat Capacity 854 J Kg-1 K-1
Dielectric Constant 6.76 at 1MHz (7) Youngs Modulus (E) 75.8 GPa (7)
Shear Modulus (G) 33.77 GPa (7) Bulk Modulus (K) 82.71 GPa (7)
Elastic Coefficients C11 = 164 C12 = 53 C44 = 33.7 (7) Apparent Elastic Limit 36.54 MPa
Poisson Ratio 0.26 Solubility 0.0017g/100g water at 20°C
Molecular Weight 78.08 Class/Structure Cubic (111) cleavage

Due to its high average transmission and low chromatic aberration relative to other IR materials, calcium fluoride (or CaF2 ) is an excellent choice for windows and lenses for spectroscopy applications in the deep UV to near IR wavelength range (180 nm-8 µm). For its good transmission properties at MWIR range, the CaF2 are often selected as the lenses for MWIR (3-5 micro)thermal imaging applications.

Curves:
Transmission curve of the CaF2 substrates of different thickness