Barium Fluoride (BaF₂) is a high-performance optical crystal known for its exceptionally broad spectral transmission, extending from the deep ultraviolet (DUV) to the mid-infrared (IR). With excellent optical clarity, low absorption, and fast scintillation response, BaF₂ is widely used in UV optics, infrared systems, spectroscopy, scintillation detection, and high-energy physics applications.
High-purity BaF₂ crystals are synthetically grown to optical grade and precisely processed to ensure low scatter, high transmission, and stable thermo-mechanical performance. In addition to optical components, BaF₂ is one of the most well-known scintillation crystals for radiation detection due to its fast decay time.
Optical Properties
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Ultra-Broad Transmission Range: 0.15 – 14 μm (DUV to mid-IR)
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High Transmittance: 94% @ 0.35 – 10.8 μm (typical thickness)
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Refractive Index
1.4624 @ 2.58 μm
1.3936 @ 10.35 μm -
Reflection Loss (Uncoated)
6.8% @ 2.58 μm (both surfaces)
5.3% @ 10.35 μm (both surfaces) -
Low Absorption Coefficient: 3.2 × 10⁻⁴ cm⁻¹ @ 6 μm
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Thermo-Optic Coefficient (dn/dT): −15.2 × 10⁻⁶ /°C
Scintillation Properties
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Residual Radiation Peak: 47 nm
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Emission Peaks:
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310 nm (slow component)
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220 nm (fast component)
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Decay Constants:
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620 ns (slow)
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0.6 ns (fast)
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Light Output:
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20% (slow)
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4% (fast)
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These properties make BaF₂ highly suitable for fast radiation and particle detection.
Physical Properties
| Property | Value |
|---|---|
| Density | 4.89 g/cm³ |
| Melting Point | 1280 °C |
| Thermal Conductivity | 11.72 W·m⁻¹·K⁻¹ @286 K |
| Thermal Expansion | 18.1 × 10⁻⁶ /°C @273 K |
| Knoop Hardness | 82 kg/mm² (500 g indenter) |
| Specific Heat Capacity | 410 J·kg⁻¹·K⁻¹ |
| Dielectric Constant | 7.33 @1 MHz |
Mechanical Properties
| Property | Value |
|---|---|
| Young’s Modulus (E) | 53.07 GPa |
| Shear Modulus (G) | 25.4 GPa |
| Bulk Modulus (K) | 56.4 GPa |
| Poisson’s Ratio | 0.343 |
| Apparent Elastic Limit | 26.9 MPa (3900 psi) |
| Elastic Constants | C₁₁ = 89.2, C₁₂ = 40.0, C₄₄ = 25.4 |
Chemical & Crystal Properties
| Property | Value |
|---|---|
| Molecular Weight | 175.36 |
| Crystal Structure | Cubic system |
| Cleavage Plane | (111) |
| Solubility in Water | 0.0017 g @23 °C |
BaF₂ exhibits good chemical stability, low hygroscopicity compared with other halides, and is suitable for vacuum, UV, and radiation environments.
Typical Applications of BaF₂ Optics
- UV & VUV optics (deep-UV windows, lenses, and prisms for spectroscopy and excimer systems)
- Infrared optical systems (IR windows and components up to 14 μm)
- Scintillation & radiation detection (gamma-ray, X-ray, and particle detectors)
- Spectroscopy & analytical instrumentation (UV-Vis, IR, and Raman spectroscopy)
- Photolithography & excimer laser optics (UV laser windows and beam-handling components)
- Environmental & atmospheric sensing (UV–IR remote sensing and monitoring instruments)
Shape Optics BaF₂ Capabilities
Shape Optics Technologies supplies high-quality BaF₂ crystal materials and finished optical components, supported by over 20 years of optical manufacturing expertise.
Product & Service Offering
- BaF₂ IR viewport windows for infrared thermography (8–14 μm)
- Optical windows, lenses, and prisms for UV–IR systems
- High-quality BaF₂ scintillation crystals
- BaF₂ crystal blanks for custom fabrication
- OEM and volume production support
Manufacturing Capabilities
| Parameter | Capability |
|---|---|
| Maximum Diameter | Ø180 mm |
| Clear Aperture | ≥85% |
| Surface Flatness | λ/4 @ 633 nm |
| Surface Quality | 20/10 scratch-dig |
Why Choose Barium Fluoride (BaF₂)?
Barium Fluoride combines broadband UV–IR transmission, low absorption, fast scintillation response, and stable thermo-mechanical performance, making it ideal for:
- UV and IR optical systems
- High-speed radiation and particle detection
- Spectroscopy and analytical instruments
- Excimer laser and photolithography optics
Its unique combination of optical and scintillation properties makes BaF₂ a versatile and high-value material in both photonics and high-energy physics applications.