CaF2 Window is made from Calcium Fluoride material, which has transparent range from 170-7800nm. CaF2 has the property of Low Absorption, Low Index of Refraction and High Transmission UV.The refractive index of CaF2 is 1.4197 at 3000nm. It has little hygroscopic susceptibility and high thermal expansion coefficient.
CaF2 Windows are relatively soft and somewhat hygroscopic so polishing, coating and handling are more critical than UV Fused Silica windows.
Calcium Fluoride Windows are also applicable for a wide range of spectrum. It is particularly useful for wavelength at Er:YAG (2980nm) laser application.
| Code NO. | Material | Diameter | Thickness | Flatness |
| CaF2 Window 01 | UV CaF2 | 5 mm | 1.0 mm | λ/4 |
| CaF2 Window 02 | UV CaF2 | 10 mm | 1.5 mm | λ/4 |
| CaF2 Window 03 | UV CaF2 | 12.5 mm | 2 mm | λ/4 |
| CaF2 Window 04 | UV CaF2 | 12.7 mm | 2 mm | λ/4 |
| CaF2 Window 05 | UV CaF2 | 15 mm | 2 mm | λ/4 |
| CaF2 Window 06 | UV CaF2 | 15 mm | 2 mm | λ/4 |
| CaF2 Window 07 | UV CaF2 | 20 mm | 2 mm | λ/4 |
| CaF2 Window 08 | UV CaF2 | 20 mm | 3 mm | λ/4 |
| CaF2 Window 09 | UV CaF2 | 25 mm | 1 mm | λ/4 |
| CaF2 Window 10 | UV CaF2 | 25 mm | 3 mm | λ/4 |
| CaF2 Window 11 | UV CaF2 | 25 mm | 5 mm | λ/4 |
| CaF2 Window 12 | UV CaF2 | 25.4 mm | 1 mm | λ/4 |
| CaF2 Window 13 | UV CaF2 | 25.4 mm | 3 mm | λ/4 |
| CaF2 Window 14 | UV CaF2 | 25.4 mm | 5 mm | λ/4 |
| CaF2 Window 15 | UV CaF2 | 30 mm | 3 mm | λ/2 |
| CaF2 Window 16 | UV CaF2 | 38.1 mm | 3 mm | λ/2 |
| CaF2 Window 17 | UV CaF2 | 50.8 mm | 3 mm | λ/2 |
| CaF2 Window 18 | UV CaF2 | 50.8 mm | 5 mm | λ/2 |
| CaF2 Window 19 | IR CaF2 | 5 mm | 1.0 mm | λ/4 |
| CaF2 Window 20 | IR CaF2 | 10 mm | 1.5 mm | λ/4 |
| CaF2 Window 21 | IR CaF2 | 12.5 mm | 2 mm | λ/4 |
| CaF2 Window 22 | IR CaF2 | 12.7 mm | 2 mm | λ/4 |
| CaF2 Window 23 | IR CaF2 | 15 mm | 2 mm | λ/4 |
| CaF2 Window 24 | IR CaF2 | 15 mm | 2 mm | λ/4 |
| CaF2 Window 25 | IR CaF2 | 20 mm | 2 mm | λ/4 |
| CaF2 Window 26 | IR CaF2 | 20 mm | 3 mm | λ/4 |
| CaF2 Window 27 | IR CaF2 | 25 mm | 1 mm | λ/4 |
| CaF2 Window 28 | IR CaF2 | 25 mm | 3 mm | λ/4 |
| CaF2 Window 29 | IR CaF2 | 25 mm | 5 mm | λ/4 |
| CaF2 Window 30 | IR CaF2 | 25.4 mm | 1 mm | λ/4 |
| CaF2 Window 31 | IR CaF2 | 25.4 mm | 3 mm | λ/4 |
| CaF2 Window 32 | IR CaF2 | 25.4 mm | 5 mm | λ/4 |
| CaF2 Window 33 | IR CaF2 | 30 mm | 3 mm | λ/2 |
| CaF2 Window 34 | IR CaF2 | 38.1 mm | 3 mm | λ/2 |
| CaF2 Window 35 | IR CaF2 | 50.8 mm | 3 mm | λ/2 |
| CaF2 Window 36 | IR CaF2 | 50.8 mm | 5 mm | λ/2 |
Attribute | Specification |
Typical Diameter (Φmm) | 10.0, 12.7, 15.0, 20.0, 25.4, 50.8 |
Square Shape:WxH(mm) | 12.7x12.7,25.4x25.4,50.8x50.8 |
Typical Thickness (mm) | 1.0, 2.0, 3.0, 4.0, 6.35,12.7 |
Diameter Tolerance (mm) | +0.0/-0.1 |
Thickness Tolerance (mm) | ±0.05 |
Clear Aperture | >90% |
Parallelism | 1 arcmin |
Surface Quality | 20/10 |
Flatness(@632.8nm) | λ/4 |
Coating | Uncoated, AR, HR, PR Coating, etc. |
What is the refractive index of CaF2 window ?
| Wavelength(nm) | Refractive index | Wavelength(nm) | Refractive index |
| 170 | 1.5311 | 1550 | 1.4261 |
| 190 | 1.5046 | 2000 | 1.4239 |
| 210 | 1.4875 | 2980 | 1.4180 |
| 250 | 1.4673 | 4000 | 1.4097 |
| 355 | 1.4460 | 5000 | 1.3990 |
| 532 | 1.4354 | 6000 | 1.3856 |
| 800 | 1.4306 | 7000 | 1.3694 |
| 1064 | 1.4285 | 7800 | 1.3499 |
The Dispersion formula of CaF2 as follow:
What is the Abbe number of CaF2 window ?
The Abbe number of CaF2 is approximately 95, indicating low dispersion and suitable for applications where minimizing chromatic aberration is important, such as in high-quality optical lenses and imaging systems.
What is the Group velocity dispersion of CaF2 window ?
GVD = 41.260 fs2/mm
D = -225.10 ps/(nm km)
What is the transmittance of CaF2 window ?
CaF2 has high transmittance in the ultraviolet, visible, and infrared regions of the electromagnetic spectrum. Its approximate transmittance values are: > 90% in the UV region, > 95% in the visible region, and > 90% in the infrared region. Actual transmittance can vary based on material quality and thickness.
What is a calcium fluoride window for FTIR ?
A calcium fluoride (CaF2) window for FTIR (Fourier Transform Infrared) spectroscopy is a transparent optical component used in FTIR instruments to transmit infrared light for analyzing chemical substances. CaF2 has a wide transmission range in the infrared spectrum (approximately 170nm to 7800nm or beyond) and low absorption, making it suitable for accurate IR measurements. Careful handling is required due to its hygroscopic nature.
Know about the application of CaF2 window ?
Infrared Spectroscopy: CaF2 windows are often used in infrared spectroscopy because of their wide transmission range (from about 0.17 to 7.8 μm), making them capable of transmitting in both the ultraviolet and mid-infrared spectral regions.
Thermography: In thermographic cameras, CaF2 windows can be used because of their excellent transmission properties in the infrared range.
High Energy Systems: CaF2 windows are used in high energy systems because of their low absorption and high damage threshold. For instance, they can be utilized in laser applications, high-power UV systems, and high energy particle detection systems.
Cryogenic Systems: CaF2 windows are excellent for use in cryogenic systems as they are stable even at very low temperatures. This makes them ideal for use in telescopes or other astronomical instruments that need to function at low temperatures.
Microwave and Radio Frequency (RF) Systems: Calcium Fluoride's low dielectric constant and loss factor make it useful in microwave and RF window applications, where it can help to minimize power losses.
Lithography: CaF2 windows are also used in photolithography systems for the production of microelectronics. Because of their transparency to UV light, they are suitable for use in excimer laser systems that operate in the deep UV range.
How do you clean CaF2 windows ?
Cleaning CaF2 windows requires careful handling to avoid damage and preserve their optical properties. Here are some general steps to clean CaF2 windows effectively:
Remove Dust: Gently blow or use a soft, lint-free brush to remove any loose particles or dust from the surface of the window. Avoid using compressed air, as it may contain moisture or particles that could harm the CaF2 surface.
Prepare Cleaning Solution: Create a cleaning solution by mixing a small amount of mild detergent or lens cleaning solution with distilled water. Avoid using harsh chemicals or solvents that could damage the CaF2 material.
Dampen a Cleaning Cloth: Moisten a soft, lint-free optical cleaning cloth with the prepared cleaning solution. Make sure the cloth is not soaking wet, just slightly damp.
Gently Wipe the Surface: Lightly wipe the CaF2 surface using gentle circular motions. Do not apply excessive pressure to avoid scratching the window.
Remove Stubborn Stains: If there are stubborn stains or residues, avoid using force. Instead, let the cleaning solution soak on the stain for a few minutes, and then gently try wiping it away again.
Rinse with Distilled Water: Once the surface is clean, rinse the CaF2 window with distilled water to remove any remaining cleaning solution. Again, ensure the cloth is only slightly damp, not wet.
Dry with Compressed Air or Nitrogen: Use clean, dry compressed air or nitrogen gas to blow away any remaining water droplets from the surface. Be cautious not to use high-pressure air to avoid damaging the window.
Final Inspection: Inspect the CaF2 window under proper lighting to check for any smudges or streaks. If necessary, repeat the cleaning process.
Storage: Store the cleaned CaF2 window in a clean, dust-free container or protective sleeve to prevent contamination.
Remember, CaF2 is somewhat hygroscopic, so it is essential to avoid exposing the windows to high humidity or moisture. Always handle them with care and use clean, soft materials during the cleaning process to maintain their optical quality. If you have particularly sensitive or critical applications, it's best to consult the manufacturer's guidelines for specific cleaning procedures.
