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BaF2 Optics

BaF2 (Barium Fluoride) belongs to cubic crystal system with less moisture resistance, the melting point of 1280℃, which allows BaF2 (Barium Fluoride) components work under extremely high temperature, refractive index varies slightly in a broad wavelength range. BaF2 (Barium Fluoride) is widely used the material in UV and IR spectroscopy due to the transmission in the range from 150-200nm to 11-11.5μm.

BaF2 (Barium Fluoride) can be used to make optical components like windows and lenses. It is used in windows for infrared spectroscopy, in particular in the field of fuel oil analysis. Its transmittance at 200nm is relatively low (0.60), but at 500nm it goes up to 0.96-0.97 and stays at that level until 9μm, then it starts falling off (0.85 for 10μm and 0.42 for 12μm). The refractive index is about 1.46 from 700nm to 5μm. Honour Optics is the high transmittance UV and IR grade BaF2 optics manufacturer, purchase large size BaF2 optics, welcome to wholesale Infrared and Broadband BaF2 optics.

BaF2 (Barium Fluoride) is relatively soft but is highly sensitive to mechanical and thermal shock, BaF2 (Barium Fluoride) is less resistant to water than CaF2 (Calcium Fluoride), pronounced water attack occurs at 500 °C but still can be used up to 800°C in dry air. Maximum available size: Dia. 200 mm x Thickness 50 mm.

UV and IR grade BaF2 optics monocrystalline is ideal for use as a UV window where high radiation resistance is required from, for example, scintillation grade BaF2 is usually used as a scintillator for gamma detection. It is the fastest scintillating crystals up to now and is used in High Energy Physics Experiments. Other applications include thermography and medical thermology equipment, laser and astronomy.

UV and IR grade BaF2 optics with transmission over 90% at 0.2-10μm wavelength band, and reaching 0% at about 0.18µm and 14µm. It is a kind of soft material with a hardness of HK82, and with less moisture resistance, this makes BaF2 optics quite easy to be scratched and moistened; Although Barium Fluoride's low index of refraction of 1.48 provides high transmission, it can be used without anti-reflection coatings, it is always good to have a protective AR coating for use in the 0.8-2.5µm, 3.0-5.0µm, 1.0-5.0µm or any other ranges.

Customized plano/spherical/aspherical/cylindrical BaF2 optics standard orientation is <111>, and mainly apply in near-infrared wavelength, and also be divided into monocrystal and polycrystal. But it is very hard to growth monocrystal in large size. BaF2 is further soft and is also difficult to get a better surface quality than CaF2. So both the material itself and polishing makes BaF2 optics quite expensive.

Customized plano/spherical/aspherical/cylindrical BaF2 optics are generally used in the VIS, NIR and/or MW spectral regions. The hardness of BaF2 is about half that of CaF2. BaF2 is also more susceptible to thermal shock than CaF2. BaF2 is somewhat more expensive than CaF2. Not as readily available in large sizes as CaF2. BaF2 is diamond turnable.

Products manufactured: Spherical Lenses, Aspheric lenses, Windows, Optical Beamsplitters, Optical Filters, Wedges, Prisms.

Surface finish: Polishes of 20-10 scratch-dig are mostly specified for use in UV and visible applications. Typical specifications for surface quality in the infrared are a 40-20 scratch-dig in the 0.75 to the 3μm spectral region and 60-40 scratch-dig for the 3-7μm area.

Surface figure: a Surface figure of a 1/10 wave to 1/2 wave @0.6328 μm are specified mostly on lenses for ultraviolet and visible use. In the infrared, typically required surface figure ranges from 1/2 wave to 2 waves @0.6328 μm depending on the system performance requirements.

AR coating options: Typically available coatings for BaF2 include BBAR for 0.8 to 2.5 μm, 3 to 5μm or the 1 to 5μm spectral regions.

Tab. 1. Main Properties of BaF2

Optical Properties
Transmission Range 150 nm to 14 μm
Transmittance >94% at 350 nm to 10.8 μm
Refractive Index 1.4624 at 2.58 μm

1.3936 at 10.35 μm

Reflection Loss 6.8% at 2.58 μm (both surfaces)

5.3% at 10.35 μm (both surfaces)

Radiation Length 20.6 mm
Residual Radiation Peak 47 nm
Emission Peak 310 nm slow; 220 nm fast
Decay Constant 620 ns slow; 0.6 ns fast
Light Output 20% slow; 4% fast
Absorption Coefficient 3.2 x 10-4 cm-1 at 6 μm
dn/dT -15.2 x 10-6 /℃
Physical Properties
Density 4.89 g/cm3
Melting Point 1280℃
Thermal Conductivity 11.72 Wm-1K-1 at 286K
Thermal Expansion 18.1 x 10-6 /℃ at 273K
Knoop Hardness 82 with 500g indenter (kg/mm2)
Specific Heat Capacity 410J/(kg.k)
Dielectric Constant 7.33 at 1MHz
Youngs Modulus (E) 53.07 GPa
Shear Modulus (G) 25.4 GPa
Bulk Modulus (K) 56.4 GPa
Elastic Coefficient Elastic Coefficient
Apparent Elastic Limit 26.9 MPa (3900 psi)
Poisson Ratio 0.343
Chemical Properties
Solubility 0.0017 g/ 100g water at 23℃
Molecular Weight 175.36
Structure Cubic Crystal
Cleavage Plane (111)

Tab. 2. Refractive index of BaF2

Wavelength (µm) n
0.26 1.51
0.3 1.5
0.36 1.49
0.48 1.48
0.85 1.47
3.24 1.46
5.14 1.45
6.5 1.44
8 1.43
8.6 1.42
9.2 1.41
9.8 1.4
10.6 1.39

Tab. 3. Specification of BaF2 optics

Specification Typical Level High precision
Sizes 2mm-200mm 2mm-200mm
Diameter tolerance +/-0.1mm +/-0.05mm
Thickness tolerance +/-0.1mm +/-0.05mm
Surface quality, scr/dig 60/40 20/10
Surface flatness(lambda) 2 L/4
Parallelism 3 arc min 30 arc sec
Clear Aperture 80% 90%
Chamfer 0.25mm at 45 deg 0.15mm at 45 deg
Coating Protective AR coating Protective AR coating

Transmission Spectrum

BaF2 optics transmission spectrum

BaF2 (Barium Fluoride) is used for optical windows, lenses, and prisms in UV-IR range with its stable optical properties and good mechanical properties. Besides, it can also be used as a substrate for some applications. In addition, BaF2 (Barium Fluoride) is widely used in high energy physics, nuclear physics, and nuclear medical instruments etc. Honour Optics is the high transmittance UV and IR grade BaF2 optics manufacturer, purchase large size BaF2 optics, welcome to wholesale Infrared and Broadband BaF2 optics.
BaF2 (Barium Fluoride) is a broadband optical material with high radiation resistance enabling a broad spectrum of applications:
UV, IR, FTIR spectroscopy
Optics for astronomical instrumentation
Space optics
Laser spectroscopy
A scintillator for high-energy detection

Honour Optics is the professional manufacturer of BaF2 (Barium Fluoride) with ROHS environmental protection requirements. Honour Optics could provide:
Infrared BaF2 (Barium Fluoride) optical components with different shapes, such as rod, square, step, wedge, prism, spherical, cylindrical and so on.
BaF2 (Barium Fluoride) IR Viewport Windows for Infrared Thermography at 8μm to 14μm
Mono or polycrystal, maximum size is about 200mm
Orientation:<100>、<110>、 <111>