Barium Fluoride (BaF₂) Optical Windows
Chenyu Optics manufactures Barium Fluoride optical windows for wide spectral transmission from ultraviolet to infrared wavelengths. BaF₂ is selected for FTIR spectroscopy, broadband infrared instruments, gas analysis, research optics and applications requiring wider infrared transmission than CaF₂ or MgF₂.
Barium Fluoride Optical Windows Overview
Barium Fluoride (BaF₂) optical windows are crystalline optical components used in broadband ultraviolet, visible and infrared optical systems. BaF₂ provides wide transmission and is especially useful for infrared spectroscopy and FTIR instruments where transmission beyond the range of CaF₂ or MgF₂ is required.
BaF₂ has a relatively low refractive index and good infrared transmission, but it is a soft crystal material and is more sensitive to moisture and mechanical damage than fused silica, sapphire or MgF₂. For this reason, BaF₂ windows require careful polishing, edge finishing, handling and protective packaging.
Chenyu Optics supports custom BaF₂ optical window manufacturing according to customer drawings, including round, square, rectangular and special-shaped windows. Surface quality, flatness, parallelism, chamfer, thickness and coating can be selected according to spectroscopy, infrared sensing and research instrument requirements.
Key Advantages of Barium Fluoride Optical Windows
FTIR, Spectroscopy & Broadband IR Use
BaF₂ windows are used in FTIR spectroscopy, infrared gas analysis, broadband analytical instruments, scientific research systems and IR optical modules requiring extended wavelength coverage.
Typical Specifications of Barium Fluoride Optical Windows
| Material | Barium Fluoride / BaF₂ |
|---|---|
| Material Grade | Optical Grade BaF₂ / Infrared Grade BaF₂ |
| Transmission Range | Approx. 200 nm – 12 μm, depending on grade, thickness and coating |
| Refractive Index | Approx. 1.46 @ 1 μm |
| Density | Approx. 4.89 g/cm³ |
| Knoop Hardness | Approx. 82 kg/mm² |
| Surface Quality | 60-40, 40-20, 20-10 or custom scratch-dig |
| Surface Flatness | λ/10, λ/4, λ/2 or custom @ 632.8 nm |
| Parallelism | ≤ 10 arcsec, ≤ 1 arcmin, ≤ 3 arcmin or custom |
| Clear Aperture | ≥85%, ≥90% or drawing-based |
| Diameter / Size | Custom round, square, rectangular or special-shaped windows |
| Thickness Tolerance | ±0.1 mm, ±0.05 mm, ±0.02 mm or custom |
| Chamfer | Protective bevel, fine ground edge or drawing-based chamfer |
| Coating Options | Uncoated, UV AR, VIS-NIR BBAR, IR AR, custom broadband AR coatings |
Optical Transmission Characteristics of Barium Fluoride Optical Windows
Typical BaF₂ Transmission Curve
Barium Fluoride provides broad transmission from ultraviolet through infrared wavelengths and is often selected for FTIR spectroscopy and broadband infrared analytical instruments. Actual transmission depends on crystal quality, thickness, polishing and coating configuration.
Why Choose Chenyu Optics for Barium Fluoride Optical Windows
BaF₂ is softer and more moisture-sensitive than many optical materials, so controlled processing, edge protection and clean packaging are important. Chenyu Optics supports drawing-based BaF₂ optical window production for spectroscopy, infrared sensing and scientific instrument customers.
Manufacturing Capability for Barium Fluoride Optical Windows
Low-Stress Polishing
Controlled polishing for soft BaF₂ crystal surfaces to reduce subsurface damage, scatter and edge stress.
Optical Coating
UV AR, VIS-NIR BBAR and IR AR coating support for spectroscopy and infrared wavelength requirements.
Inspection & Packaging
Dimensional inspection, surface quality review, transmission verification and moisture-protective packaging.
Custom Manufacturing Options for Barium Fluoride Optical Windows
Dimensions & Geometry
Round, square, rectangular, wedge and special-shaped BaF₂ windows can be manufactured according to customer drawings, including custom diameter, thickness and clear aperture.
Surface & Mechanical Quality
Surface quality, flatness, parallelism, chamfer and edge treatment can be specified based on optical performance, mounting conditions and handling requirements.
Coating & Wavelength Design
Uncoated, UV AR, VIS-NIR broadband AR and infrared AR coatings can be designed for spectroscopy, gas analysis and broadband IR applications.
Barium Fluoride Optical Windows Material Comparison
| Material | Barium Fluoride (BaF₂) | Calcium Fluoride (CaF₂) | Magnesium Fluoride (MgF₂) | UV Fused Silica | Zinc Selenide (ZnSe) |
|---|---|---|---|---|---|
| Transmission | Approx. 200 nm – 12 μm | Approx. 130 nm – 10 μm | Approx. 120 nm – 7 μm | Approx. 185 nm – 2.1 μm | Approx. 0.6 – 20 μm |
| Main Advantage | Broad UV-to-IR transmission with extended IR coverage | Low dispersion and strong UV-to-IR balance | VUV transmission and better durability | Excellent UV performance and high thermal stability | Strong IR transmission for CO₂ laser and IR optics |
| Mechanical Behavior | Very soft, moisture-sensitive, careful handling required | Soft crystal, sensitive to shock and stress | Harder fluoride crystal, birefringent | Harder and more thermally stable | Soft material, requires careful handling |
| Typical Use | FTIR spectroscopy, IR instruments, broadband windows | UV spectroscopy, excimer lasers, broadband windows | VUV windows, excimer lasers, high-vacuum optics | UV lasers, optical flats, machine vision windows | IR windows, lenses and CO₂ laser optics |
Applications of Barium Fluoride Optical Windows
FTIR Spectroscopy
BaF₂ windows for Fourier-transform infrared spectrometers and broadband analytical instruments.
Infrared Spectroscopy
Gas analysis cells, sample windows and IR optical paths requiring wide spectral transmission.
UV-Visible Instruments
Broadband UV-visible optical instruments where extended IR transmission is also required.
Research Equipment
Laboratory optical setups, cryostats and vacuum chambers requiring UV-to-IR transmission.
Gas Analysis
Optical windows for gas cells, environmental monitoring and molecular absorption measurements.
Infrared Sensors
Broadband IR detector windows and analytical sensor assemblies.
Barium Fluoride Optical Windows FAQ
What wavelength range can Barium Fluoride optical windows transmit?
BaF₂ typically transmits from approximately 200 nm to 12 μm, depending on material grade, thickness, surface quality and coating design.
How does BaF₂ compare with CaF₂?
BaF₂ usually provides extended infrared transmission compared with CaF₂, making it useful for FTIR and broadband infrared spectroscopy. CaF₂ is generally stronger mechanically and more commonly used where UV performance and handling stability are important.
Is Barium Fluoride moisture sensitive?
Yes. BaF₂ is more sensitive to moisture and handling than CaF₂, fused silica or sapphire. Long-term exposure to moisture, condensation or aggressive cleaning can degrade the surface, so protective handling and packaging are recommended.
Is BaF₂ suitable for outdoor optical windows?
BaF₂ is not normally the first choice for harsh outdoor windows because it is soft and moisture-sensitive. For outdoor systems, materials such as sapphire, fused silica, CaF₂, ZnSe or coated protective window designs may be more suitable depending on wavelength.
Can Barium Fluoride windows be AR coated?
Yes. BaF₂ windows can be supplied uncoated or with UV AR, VIS-NIR broadband AR, infrared AR or custom coatings. Coating design should consider the material softness and environmental exposure.
What information should I provide for quotation?
Please provide wavelength range, size, thickness, surface quality, flatness, parallelism, clear aperture, coating requirements, quantity, operating environment and drawing if available.
Where can I learn more about Barium Fluoride optical materials?
Additional Barium Fluoride material information can be found from Edmund Optics.
Related Products for Barium Fluoride Optical Windows
Need Custom Barium Fluoride Optical Windows?
Send us your BaF₂ wavelength range, size, thickness, coating requirements, quantity, operating environment and drawing. Chenyu Optics will review the optical and mechanical requirements and provide a suitable manufacturing suggestion.