Features
● High transmittance in VIS and extended IR range up to 12µm
● Low refractive index (nd = 1.47447)
● Low spectral dispersion (vd = 81.61)
● Available up to 360 mm diameter
Physical/Optical Characteristics
| Transmission Range : | 0.15 to 12 μm (Note: IR grade may have restricted performance in UV) |
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 Fm3m (#225) Fluorite structure. Cleaves on (111) |
Not all crystal is manufactured from the highest grade of chemical; for IR grade optics a lower specification of raw material is adequate and reduces cost, however the transmission in the UV may be restricted.
µm | No | µm | No | µm | No |
0.1408 | 1.8150 | 0.1452 | 1.7820 | 0.1477 | 1.7670 |
0.1500 | 1.6780 | 0.2000 | 1.557 | 0.2652 | 1.5122 |
0.2803 | 1.5066 | 0.2893 | 1.5039 | 0.2967 | 1.5019 |
0.3021 | 1.5004 | 0.3130 | 1.4978 | 0.3254 | 1.4952 |
0.3403 | 1.4925 | 0.3466 | 1.4915 | 0.3610 | 1.4894 |
0.3663 | 1.4887 | 0.4046 | 1.4844 | 0.5461 | 1.4759 |
0.5893 | 1.4744 | 0.6438 | 1.4730 | 0.6563 | 1.4727 |
0.7065 | 1.4718 | 0.8521 | 1.4699 | 0.8944 | 1.4694 |
1.0140 | 1.4685 | 1.1287 | 1.4678 | 1.3673 | 1.4667 |
1.5295 | 1.4661 | 1.6810 | 1.4656 | 1.7012 | 1.4655 |
1.9701 | 1.4647 | 2.3254 | 1.4636 | 2.6738 | 1.4623 |
3.2434 | 1.4602 | 3.4220 | 1.4594 | 5.1380 | 1.4501 |
5.5490 | 1.44732 | 6.2380 | 1.4422 | 6.6331 | 1.4390 |
7.0442 | 1.4353 | 7.2680 | 1.4331 | 9.7240 | 1.4051 |
10.346 | 1.3936 |
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❈ No = Ordinary Ray
Barium Fluoride is grown by vacuum Stockbarger technique. Unlike CaF2, BaF2 is not found in the native state and all material must be synthesised chemically making BaF2 relatively expensive to produce. Barium Fluoride cleaves easily and is highly susceptible to thermal shock. It polishes well and can be etched (5).
Not all crystal is manufactured from the highest grade of chemical; for IR grade optics lower specification is adequate and reduces cost, however the transmission in the UV and VUV is restricted.
The highest purity Barium Fluoride VUV material can be qualified as fast scintillator grade. (6)
Spectral Transmission BaF2
Application
BaF2 is an excellent optical material for a broad spectral range in VIS and IR. This enables utilization in sophisticated applications:
● Thermal imaging and night vision with integrated VIS channel
● Optics for astronomical instrumentation
● Infrared laser optics
● Scintillator for the detection of high energy γ-radia
