Calcium Fluoride CaF2 Optical Window

K9 optical window
  • Calcium fluoride (CaF2) and magnesium fluoride (MgF2) crystals have high hardness, strong resistance to mechanical shock and thermal shock, and good transmittance in ultraviolet, infrared and infrared bands. They are widely used in lasers, infrared optics, ultraviolet optics and high-energy detectors.

  • In particular, they have good optical properties in the ultraviolet band. They are currently known optical crystals in the ultraviolet cutoff band, with high transmittance and low fluorescence radiation. They are ideal materials for ultraviolet photodetectors, ultraviolet lasers and ultraviolet optical systems. Unlike calcium fluoride (CaF2), magnesium fluoride (MgF2) is a birefringent crystal.

Technical parameters
Items Parameters
Material Calcium fluoride (CaF2)
Processable shapes Circles, rectangles, polygons and other shapes
Diameter 3mm-300mm ± 0.1mm
Center thickness tolerance ± 0.05mm (we can process to ± 0.01mm with high precision)
Center deviation 3′(we can process to 30 ″with high precision)
Surface accuracy Reflection PV is better than 1/4λ, transmission PV is better than 1/10λ
Surface quality 40/20 (we can process to 10-5 with high precision)
Effective caliber ≥90%
Coating According to the custom requirements
spectral curve

Physical and chemical properties of calcium fluoride CaF2

Density (g/cm3) 3.18
Melting point (℃) 1360
Dielectric constant 6.76@1HMZ
Chemical purity (%) 99.9996
Thermal expansion coefficient (1/℃) 18.85*10^-6
Thermal conductivity (J/k.m.s) 9.71
Heat capacity (J/g.k) 0.854
Knoop hardness (kg/mm2) 158.3
Shear modulus (GPa) 33.77
Young's modulus(GPa) 75.8
Poisson's ratio 0.26

Optical properties of calcium fluoride Caf2

Transmission wavelength range 130nm-10000nm
Refractive index inhomogeneity (ΔN/N) <3*10^-6@632.8nm
Reflection loss (2 sides) 5.4%@5000nm
Thermo-optic coefficient, dn/dT (1/℃) -10.6*10^-6

Variation of refractive index with wavelength

Wavelength (nm) Refractive index (n) Wavelength (nm) Refractive index (n)
190 1.51 2650 1.42
210 1.49 3900 1.41
250 1.47 5000 1.40
330 1.45 6200 1.38
410 1.44 7000 1.36
880 1.43 8220 1.34

In addition, We can customize the optical window according to customer requirements or drawings.

For details, please consult:

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