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BaF2 Lenses

Features:

  • Wide wavelength range of 0.2-11 μm
  • Suitable for MWIR (3-5 μm) thermal cameras

Curves All Inquire Us  

Specifications:

Materials BaF2 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 0.15 to 12 μm Refractive Index 1.45 at 5 μm (1)
Reflection Loss 6.5% at 5 μm (2 surfaces) Absorption Coefficient 3.2 x 10-4 cm-1 @ 6 μm
Reststrahlen Peak 47 μm dn/dT -15.2 x 10-6 /°C (2)
dn/dμ = 0 1.95 μm Density 4.89 g/cc
Melting Point 1386°C Thermal Conductivity 11.72 W m-1 K-1 @ 286 K
Thermal Expansion 18.1 x 10-6 /°C @ 273 K Hardness Knoop 82 with 500g indenter (4)
Specific Heat Capacity 410 J Kg-1 K-1 (3) Dielectric Constant 7.33 at 1 MHz
Youngs Modulus (E) 53.07 GPa (3) Shear Modulus (G) 25.4 GPa (3)
Bulk Modulus (K) 56.4 GPa Elastic Coefficients C11 = 89.2 C12 = 40.0 C44 = 25.4 (2)
Apparent Elastic Limit 26.9 MPa (300psi) (4) Poisson Ratio 0.343
Solubility 0.17g/100g water at 23°C Molecular Weight 175.36
Class/Structure Cubic CaF2, Fm3m, (111) cleavage

Barium Fluoride or BaF2 crystals could be used in the ultraviolet, visible and infrared spectral regions. BaF2 has a good transmission above 90% between 0.25 and 9.5µm. Barium Fluoride is half as hard as Calcium Fluoride and also more susceptible to thermal shock. However, it is commonly used in cryogenically cooled thermal imaging systems, Hangzhou Shalom EO offer the BaF2 lenses used in MWIR (3-5 micro) thermal imaging applications.

Curves:
Transmission curve of the BaF2 substrates of different thickness