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Barium Fluoride (BaF2)

Download BaF2 (Barium Fluoride) Datasheet (PDF, 252 KB)

BaF2

BaF2 (Barium Fluoride) is widely used material in UV and IR spectroscopy due to the transmission in range from 0.2 to 11μm. It is very sensitive to mechanical and thermal shock. Can be used in IR laser applications. Barium Fluoride is less resistant to water than Calcium Fluoride but still can be used up to 800°C in dry air.

Application

  • UV, IR, FTIR spectroscopy
  • Laser spectroscopy

Product types

  • Plane-parallel windows and wedges
  • Lenses
  • Prisms

Specification

Tab.1. Typical specification of BaF2 optical components

Specification Typical State-of-the-art
Sizes See table in the article Plane Windows and Wedged Windows Up to 150 mm
Diameter tolerance, mm +0/-0.25 RFQ
Thickness tolerance, mm ±0.25 RFQ
Thickness matching, mm — RFQ
Surface quality, scr/dig 60/40 20/10
Surface flatness, λ @ 633nm per inch* 2 1/4
Parallelism (wedge tolerance) 5 arc min 5 arc sec
Coating none beamsplitting

* For “thick” windows: while Diameter/Thickness ratio ≤8

Transmission Spectrum

BaF2

Fig. 1. The measurements were carried out on Perkin Elmer Lambda-35 spectrophotometer and on BrukerVertex-70 Fourier-spectrometer.


Tab.2. Refractive index

λ, µm n
0.26 1.51
0.30 1.50
0.36 1.49
0.48 1.48
0.85 1.47
3.24 1.46
5.14 1.45
6.50 1.44
8.00 1.43
8.60 1.42
9.20 1.41
9.80 1.40
10.60 1.39

 

 Tab.3. Optical properties

Transmission range, µm 0,2 — 11
Colour Colourless
Reflection losses @ 5 µm (2 surfaces), % 5,3
Restrahlen peak, μm 47
dN/dT, 10-6/C -15.2
dN/dμ = 0, μm 1.95


Tab.4. Physical and mechanical properties

Class / Structure Cubic FCC, Fm3m, (111)
cleavage
Density @300K, g/cm3 4.83
Molecular Weight 175.36
Lattice Constant, Å 6.196
Melting Point, °C 1368
Thermal Conductivity @319K, W/(mxK) 11.72
Thermal Expansion @300K, 10-6/C 18.1
Hardness, Knoop with 500 g indenter 82 (100)
Specific Heat Capacity, J/(kg×K) 410
Dielectric Constant for 106 Hz 7.33
Young Modulus (E), GPa 53.07
Shear Modulus (G), GPa 25.4
Bulk Modulus (K), GPa 56.4
Elastic Coefficient C11 = 89.2, C12 = 40.0,
C44 = 25.4 MPa
Apparent Elastic Limit, MPa 26.9
Poisson Ratio 0.343

Tab.5. Chemical stability / Solubility

in water
(at 0оС)		 0,17 g / 100 cm3
non-hygroscopic
in acids soluble
in organic solvents:  
acetone insoluble
lower spirits slightly insoluble
ether insoluble

Please pay your attention that this article is for your information only. We do not supply BaF2 in ingots as well as semi-finished products. Our standard products are polished parts.

For further information on our BaF2 optical components please see the following: Windows for IR-spectroscopy, FTIR Beam Splitter, Packaging or fill in our request form.

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