Barium Fluoride (BaF2)
Optical crystal transmitting from deep-UV through long-wave infrared
UV–IR Optical Crystal
Barium Fluoride is a broadband optical crystal with transmission extending from the deep ultraviolet through to the long-wave infrared. It is commonly specified in spectroscopy, FTIR, and radiation-exposed environments due to its low absorption and resistance to radiation darkening. While mechanically softer than many oxide crystals, BaF₂ is valued for applications requiring a single material solution across a very wide spectral range.
Is this material right for your application?
Use When:
Avoid When:
Consider Alternatives:
Broad transmission from UV through long-wave IR is required
A single material must cover multiple spectral regions
FTIR or spectroscopy systems are used
Radiation resistance is important (space, nuclear environments)
Low absorption across a wide wavelength range is critical
Mechanical strength and hardness are critical
Components will be exposed to moisture without protection
High abrasion or handling damage is likely
Cost-sensitive visible-only systems are being designed
High mechanical shock or vibration is expected
Calcium Fluoride (CaF₂) – improved mechanical strength and lower hygroscopicity
Magnesium Fluoride (MgF₂) – better durability for UV-focused applications
Zinc Selenide (ZnSe) – mid-IR performance with greater mechanical robustness
Key Properties
Optical
Very broad transmission from deep-UV to long-wave IR
Low refractive index
Low absorption across wide wavelength range
Mechanical
Mechanically soft
Susceptible to surface damage
Environmental
Slightly hygroscopic
Good resistance to radiation darkening
Explore Related Optical Materials
Frequently asked questions about Barium Fluoride specifications and use-cases
FAQ
Q1. What wavelength range is BaF₂ used for?
BaF₂ transmits from the deep UV (~150 nm) through to the mid-IR (~11 µm), making it suitable for UV, visible, and infrared applications.
Q2. Is BaF₂ hygroscopic?
Yes. BaF₂ is mildly hygroscopic and should be handled and stored in controlled environments.
Q3. Is BaF₂ mechanically robust?
No. BaF₂ is relatively soft and brittle compared to oxide glasses and requires careful handling.
Q4. What are common alternatives to BaF₂?
Calcium Fluoride (CaF₂), Lithium Fluoride (LiF), and Zinc Sulphide (ZnS) depending on wavelength and durability requirements.
BaF₂ is commonly used in FTIR spectroscopy and scintillation applications.
Anti-reflection coatings can be applied but must be compatible with fluoride substrates.
Not recommended for high-humidity or high-shock environments.