Calcium Fluoride (CaF₂) Optical Windows
Chenyu Optics manufactures Calcium Fluoride optical windows for broadband optical systems from deep ultraviolet to infrared wavelengths. UV grade CaF₂ is suitable for VUV/DUV spectroscopy and excimer laser applications, while standard optical grade CaF₂ is used for spectroscopy, infrared sensing and analytical instruments.
Calcium Fluoride Optical Windows Overview
Calcium Fluoride (CaF₂) optical windows are used where one optical material must cover ultraviolet, visible and infrared wavelengths. CaF₂ provides broad transmission, low refractive index and low dispersion, making it useful for spectroscopy, laser systems, semiconductor inspection and broadband optical instruments.
Compared with common optical glass, Calcium Fluoride offers useful transmission into both the ultraviolet and infrared regions. UV grade CaF₂ is selected for VUV/DUV systems, including 193 nm and 248 nm excimer laser wavelengths. Standard optical grade CaF₂ is typically used for UV-visible-NIR systems, infrared sensors and analytical instruments.
Chenyu Optics supports custom CaF₂ window manufacturing according to drawings, including round, square, rectangular and special-shaped windows. Surface quality, flatness, parallelism, chamfer and coating can be specified according to the optical system and mounting requirements.
Key Advantages of Calcium Fluoride Optical Windows
UV, Spectroscopy & Infrared Applications
CaF₂ windows are used in UV spectroscopy, fluorescence systems, semiconductor inspection, laser systems, infrared sensors and broadband analytical instruments.
Typical Specifications of Calcium Fluoride Optical Windows
| Material | Calcium Fluoride / CaF₂ |
|---|---|
| Material Grade | Standard Optical Grade CaF₂ / UV Grade CaF₂ / VUV Grade CaF₂ |
| Transmission Range | Approx. 130 nm – 10 μm, depending on grade, thickness and coating |
| Refractive Index | Approx. 1.40 @ 1 μm |
| Density | Approx. 3.18 g/cm³ |
| Knoop Hardness | Approx. 158 kg/mm² |
| Surface Quality | 60-40, 40-20, 20-10 or 10-5 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%, ≥95% 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 Calcium Fluoride Optical Windows
UV Grade CaF₂ Transmission Curve
UV grade Calcium Fluoride is selected for deep ultraviolet and vacuum ultraviolet optical systems. It is commonly used for excimer lasers, UV spectroscopy, fluorescence instruments and semiconductor inspection systems.
Standard Optical Grade CaF₂ Transmission Curve
Standard optical grade Calcium Fluoride provides broad transmission from the ultraviolet through the infrared region and is suitable for spectroscopy, analytical instruments, infrared sensors and broadband optical assemblies.
Why Choose Chenyu Optics for Calcium Fluoride Optical Windows
Calcium Fluoride is softer and more fragile than fused silica or sapphire, so crystal orientation, low-stress processing, edge finishing and careful packaging are important for reliable use. Chenyu Optics supports custom CaF₂ optics from prototype quantities to repeat production.
Manufacturing Capability for Calcium Fluoride Optical Windows
Low-Stress Polishing
Controlled polishing for CaF₂ surfaces to reduce subsurface damage, scatter and edge stress.
Optical Coating
UV AR, VIS-NIR BBAR and IR AR coating support for different wavelength requirements.
Inspection & Packaging
Dimensional inspection, surface quality review, transmission verification and clean packaging.
Custom Manufacturing Options for Calcium Fluoride Optical Windows
Dimensions & Geometry
Round, square, rectangular, wedge and special-shaped CaF₂ windows can be manufactured according to customer drawings, including custom thickness and clear aperture requirements.
Surface & Mechanical Quality
Surface quality, flatness, parallelism, chamfer and edge treatment can be specified based on optical performance and mounting conditions.
Coating & Wavelength Design
Uncoated, UV AR, VIS-NIR broadband AR and infrared AR coatings can be designed for spectroscopy, laser and sensor applications.
Calcium Fluoride Optical Windows Material Comparison
| Material | Calcium Fluoride (CaF₂) | UV Fused Silica | Barium Fluoride (BaF₂) | Sapphire | Zinc Selenide (ZnSe) |
|---|---|---|---|---|---|
| Transmission | Approx. 130 nm – 10 μm | Approx. 185 nm – 2.1 μm | Approx. 200 nm – 12 μm | UV to approx. 5 μm | Approx. 0.6 – 20 μm |
| Main Advantage | Broad UV-to-IR transmission and low dispersion | Excellent UV performance and high thermal stability | Extended IR transmission compared with CaF₂ | High hardness and mechanical durability | Strong IR transmission for CO₂ laser and IR optics |
| Typical Use | UV spectroscopy, excimer lasers, broadband windows | UV lasers, optical flats, machine vision windows | IR spectroscopy and broadband IR instruments | Protective windows, harsh environment optics | IR windows, lenses and CO₂ laser optics |
Applications of Calcium Fluoride Optical Windows
UV Spectroscopy
VUV and DUV spectrometers, fluorescence instruments and analytical systems.
Excimer Lasers
CaF₂ windows for 193 nm, 248 nm and ultraviolet laser applications.
Semiconductor Inspection
Optical windows for wafer inspection, photomask inspection and UV metrology.
Spectroscopy
Sample cell windows, gas analysis optics and broadband analytical instruments.
Infrared Sensors
Broadband CaF₂ windows for IR detectors and multi-wavelength sensor assemblies.
Research Systems
Cryostats, vacuum chambers and laboratory optical setups requiring wide transmission.
Calcium Fluoride Optical Windows FAQ
What is the difference between UV grade and standard Calcium Fluoride?
UV grade CaF₂ uses higher-purity crystal material and is selected for deep ultraviolet and vacuum ultraviolet applications. Standard optical grade CaF₂ is normally suitable for visible, near-infrared and infrared applications where extreme UV transmission is not required.
What wavelength range can Calcium Fluoride optical windows transmit?
CaF₂ can transmit from approximately 130 nm to 10 μm, depending on material grade, thickness, surface quality and coating design. UV grade material is required for the shortest ultraviolet wavelengths.
Is Calcium Fluoride suitable for infrared applications?
Yes. Calcium Fluoride is suitable for many infrared optical systems, especially where broadband transmission and low dispersion are required. For long-wave infrared systems beyond the useful CaF₂ range, materials such as BaF₂, ZnSe or Germanium may be considered.
Is Calcium Fluoride fragile?
Yes. CaF₂ is a relatively soft crystalline material and is more sensitive to mechanical stress and thermal shock than fused silica or sapphire. Proper chamfer design, low-stress mounting and careful handling are recommended.
Can Calcium Fluoride windows be AR coated?
Yes. CaF₂ windows can be supplied with UV AR, VIS-NIR broadband AR, infrared AR or custom coating designs depending on the wavelength range and application conditions.
What information should I provide for quotation?
Please provide material grade, wavelength range, size, thickness, surface quality, flatness, parallelism, clear aperture, coating requirements, quantity and drawing if available.
Where can I learn more about Calcium Fluoride optical materials?
Additional Calcium Fluoride material information can be found from Edmund Optics.
Related Products for Calcium Fluoride Optical Windows
Need Custom Calcium Fluoride Optical Windows?
Send us your CaF₂ material grade, wavelength range, size, thickness, coating requirements, quantity and drawing. Chenyu Optics will review the optical and mechanical requirements and provide a suitable manufacturing suggestion.