Exceptional Spectral Range
Useful transmission from approximately 0.15 to 12.5 µm, depending on optical grade, thickness, surface finish, and coating.
Optical Fluoride Crystal
Barium Fluoride (BaF₂)
Broad UV-to-Infrared Transmission for Specialized Optical Systems.
A cubic fluoride crystal offering broad ultraviolet-to-infrared transmission, low refractive index, and useful performance for spectroscopy, thermal sensing, scintillation detection, and specialized analytical optical systems.
Why Barium Fluoride
A Broad-Spectrum Fluoride Crystal for UV and Infrared Optics
Barium fluoride combines broad spectral transmission with low refractive index and strong infrared reach. It is selected for UV and infrared spectroscopy, thermal sensing, scintillation detection, and specialized analytical instruments.
Low Refractive Index
Low index reduces uncoated Fresnel reflection and supports high transmission across broad wavelength bands.
Low Dispersion
Broad UV-to-IR transmission supports multispectral and spectroscopy systems that require one material across a wide wavelength range.
Low Stress Birefringence
Cubic crystal symmetry makes BaF₂ optically isotropic, simplifying polarization-sensitive system design.
Engineering Properties
Optical, Mechanical, and Thermal Characteristics
Representative values for optical-grade barium fluoride. Final values vary by crystal grade, wavelength, orientation, thickness, supplier specification, and test method.
Physical & Mechanical Properties
| Chemical Formula | BaF₂ |
|---|---|
| Crystal Structure | Cubic fluorite structure |
| Density | Approximately 4.89 g/cm³ |
| Knoop Hardness | Approximately 82 |
| Young’s Modulus | Approximately 53 GPa |
| Poisson’s Ratio | Approximately 0.34 |
| Thermal Expansion | Approximately 18.1 × 10⁻⁶/K |
| Melting Point | Approximately 1291°C |
Optical Properties
| Transmission Range | Approximately 0.15–12.5 µm, grade and thickness dependent |
|---|---|
| Refractive Index nd | Approximately 1.47 |
| Abbe Number Vd | Approximately 81 |
| Birefringence | Isotropic cubic crystal; low stress birefringence when properly processed |
| Reflection Loss | Low relative to many optical materials due to low refractive index |
| Coating Compatibility | UV, VIS, NIR, MWIR AR, beamsplitter, and custom coatings |
| Available Grades | UV, optical, infrared, and scintillation grades |
Optical Transmission
Broad Transmission from Ultraviolet to Long-Wave Infrared
BaF₂ provides broad UV-to-infrared transmission. Actual performance depends on crystal grade, thickness, surface condition, moisture protection, and coating design.
Representative only. Final transmission depends on grade, thickness, surface finish, absorption bands, and coating.
Material Comparison
When Barium Fluoride Is the Best Fit
| Property | Sapphire | BK7 | Fused Silica | BaF₂ |
|---|---|---|---|---|
| Deep-UV Performance | Very Good | Limited | Excellent | Excellent |
| Infrared Reach | Good | Limited | Limited | Excellent |
| Chromatic Dispersion | Moderate | Low | Low | Very Low |
| Scratch Resistance | Excellent | Moderate | Good | Low |
| Thermal Expansion | Low | Moderate | Very Low | Higher |
Manufacturing Capabilities
From BaF₂ Crystal Blank to Finished Optical Component
COE Sapphire supports prototype, low-volume, and repeat production of precision barium fluoride optics with controlled fabrication, coating, and inspection.
Precision Machining
Controlled cutting, edging, beveling, drilling, and custom geometry fabrication for a relatively soft fluoride crystal.
Optical Polishing
Precision flat, spherical, and custom polishing with process controls for surface quality, subsurface damage, and edge integrity.
Optical Coating
UV, visible, NIR, MWIR, LWIR AR, beamsplitter, and application-specific multilayer coatings.
Quality Assurance
Dimensional inspection, interferometry, surface inspection, transmission verification, and documentation.
Design Guide
Specify the Right Barium Fluoride Optical Component
Provide optical grade, operating wavelength, dimensions, tolerances, surface quality, flatness or power, wedge or parallelism, clear aperture, edge treatment, coating, quantity, and environmental requirements.
Discuss Your SpecificationMaterial GradeUV, optical, IR, or scintillation grade
Surface QualityCommercial through precision optical grades
Flatness / PowerApplication-specific interferometric control
Wedge / ParallelismPrecision parallel, wedged, or custom geometry
Edge TreatmentProtective bevel or chamfer recommended for fragile edges
CoatingsUV, VIS, NIR, MWIR, beamsplitter, and custom coatings
Related Optical Components
Barium Fluoride Components Manufactured to Your Specification
Frequently Asked Questions
Barium Fluoride FAQ
What is barium fluoride commonly used for?
BaF₂ is used for UV and infrared spectroscopy, thermal sensing, scintillation detection, analytical instruments, and specialized broadband optical systems.
What wavelength range can BaF₂ transmit?
High-quality barium fluoride can provide useful transmission from the deep ultraviolet into the infrared, commonly cited at approximately 0.15–12.5 µm depending on grade and thickness.
How does barium fluoride compare with fused silica?
Both materials provide strong UV performance. BaF₂ extends farther into the infrared and has lower dispersion, while fused silica is generally tougher, has far lower thermal expansion, and is easier to process.
Is barium fluoride birefringent?
BaF₂ has a cubic crystal structure and is intrinsically isotropic. Residual stress from processing or mounting can still introduce stress birefringence.
Does barium fluoride require special handling?
Yes. BaF₂ is relatively soft and moisture-sensitive compared with fused silica or sapphire, so protective edge design, clean handling, careful mounting, and controlled cleaning are recommended.
Can barium fluoride be optically coated?
Yes. BaF₂ is compatible with UV, visible, near-infrared, mid-infrared, beamsplitter, and custom multilayer coatings when coating design and process conditions are matched to the substrate.
Can COE Sapphire manufacture custom BaF₂ shapes and tolerances?
Yes. COE Sapphire can manufacture custom windows, lenses, prisms, wedges, apertures, holes, edge treatments, and application-specific tolerances.
What information is needed for a BaF₂ quotation?
Please provide material grade, wavelength range, dimensions, tolerances, surface quality, flatness or power, wedge or parallelism, clear aperture, coating, quantity, and inspection requirements.
Custom Barium Fluoride Optical Components
Request a QuoteReady to Discuss Your BaF₂ Project?
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