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CaF2 Optics

CaF2 (calcium fluoride) shows good optical and thermo-mechanical properties. It is widely used as optical windows, lenses, and prisms in 0.13μm~10μm, used for uv and ir spectral high transmission applications as well as for laser applications. For its optical isotropy, outstanding laser power damage threshold, low absorption, and refractive index, CaF2 (calcium fluoride) have found unique advantages in high power laser and vu laser optics, which can be used without anti-reflection coating for non-laser applications.

CaF2 (calcium fluoride) components are difficult to manufacture in actual production. The material itself is soft and easy to leave fabrication marks and scratches on the polished surfaces. Honour optics also provides polishing service. At honour optics, our expertise in understanding the crystal structure gives us an advantage and enable us to offer very good surface accuracy, our standard surface quality grade is 60/40, high precision 10/5. Honour optics is the professional high transmittance laser grade CaF2 optics and vuv, uv and ir grade CaF2 optics manufacturer, welcome to consult purchase plano/spherical/aspherical/cylindrical CaF2 optics optimal price.

CaF2 (calcium fluoride) is optically isotropic, non-hygroscopic and insoluble in most acids and alkali, therefore, the polished surfaces are practically not degraded in normal atmospheric conditions. A high mechanical strength makes it useful for high-pressure applications. CaF2 (calcium fluoride) is also very sensitive to thermal shock.

Degradation due to moisture in the atmosphere is minimal, and polished surfaces of the CaF2 windows may be expected to withstand several years’ exposure to normal atmospheric conditions. In additional, CaF2 crystals are non-axial, so there is no need to consider the axial direction.

CaF2 (calcium fluoride) is attacked by atmospheric moisture about 600°c, where it begins to soften. The maximal temperature to use is about 800c when moisture is not present. Irradiation of CaF2 windows causes some losses in the uv range.

High quality chinese CaF2 optics is used in the uv, vis, nir and/ or the mw spectral regions. It is about twice as hard as baf2. CaF2 is less susceptible to thermal shock than baf2. CaF2 does not degrade due to moisture under ambient atmospheric conditions. CaF2 is less expensive than baf2. CaF2 is more readily available in large sizes than baf2. CaF2 is diamond turnable.

Products manufactured: Spherical and cylindrical lenses, aspheric lenses, windows, optical beamsplitters, optical filters, wedges, prisms.

Surface finish: Polishes of 20-10 scratch-dig are mostly specified for use in uv and visible applications. Typical specifications for surface quality in the infrared are a 40-20 scratch-dig in the 0.75 to the 3μm spectral region and 60-40 scratch-dig for the 3-7μm area.

Surface figure: In the uv and visible spectral regions, surface figure ranges from 1/10 wave to 1/4 wave @ 0.6328μm. In the infrared, typically required surface figure ranges from 1/4 wave to 2 waves @ 0.6328 μm and are specified depending on the system performance requirements.

Ar coating options: Available coatings for customized large size and special shape CaF2 optics include bbar for 0.8 to 2.5μm, 3 to 5μm or the 1 to 5μm spectral regions

Tab. 1. Main properties of CaF2

Optical properties
Transmission range 130 nm to 10 μm
Transmittance >94% at 193 nm to 7.8 μm
Refractive index 1.39908 at 5 μm
Reflection loss 5.4% at 5 μm (both surfaces)
Absorption coefficient 0.03 cm-1 at 2.6 μm to 2.9 μm
Dn/dt -10.6 x 10-6 /℃
Physical properties
Density 3.18 g/cm3
Melting point 1360℃
Thermal conductivity 9.71 wm-1k-1 at 286k
Thermal expansion 18.85 x 10-6 /℃ at 273k
Knoop hardness 158.3 with 100g indenter (kg/mm2)
Specific heat capacity 854 j/(kg.k)
Dielectric constant 6.76 at 1mhz
Youngs modulus (e) 75.80 gpa
Shear modulus (g) 33.77 gpa
Bulk modulus (k) 82.71 gpa
Elastic coefficient C11=164; c12=53; c44=33.7
Apparent elastic limit 36.54 mpa (3900 psi)
Poisson ratio 0.26
Chemical properties
Solubility 0.0017 g/ 100g water at 20℃
Molecular weight 78.08
Structure Cubic crystal
Cleavage plano (111)

Tab. 2. Refractive index of CaF2

µm No µm No µm No
0.149 1.5800 0.161 1.5490 0.195 1.5000
0.200 1.4950 0.222 1.4800 0.248 1.4680
0.266 1.4621 0.280 1.4584 0.300 1.454
0.337 1.4481 0.400 1.4419 0.486 1.4370
0.588 1.4339 0.656 1.4325 0.687 1.4320
0.728 1.4314 0.884 1.4298 1.014 1.4288
1.100 1.4283 1.250 1.4275 1.650 1.4256
1.900 1.4244 2.058 1.4236 2.450 1.4214
2.700 1.4199 2.800 1.4192 3.050 1.4175
3.400 1.4149 4.000 1.4096 4.400 1.4057
4.800 1.4014 5.000 1.3991 5.304 1.3952
5.893 1.3871 6.483 1.3782 7.072 1.3681
7.661 1.357 8.251 1.3444 8.840 1.3308
9.429 1.3161

Tab. 3. Specification of CaF2 options

Specification Typical level High precision
Sizes 2mm-300mm 2mm-300mm
Diameter tolerance +/-0.1mm +/-0.05mm
Thickness tolerance +/-0.1mm +/-0.05mm
Surface quality, scr/dig 60/40 10/5
Surface flatness(lambda) L/2 L/10
Parallelism 3 arcmin 10 arcsec
Clear aperture 80% 90%
Chamfer 0.25mm at 45 deg 0.15mm at 45 deg
Coating As requested As requested

Transmission spectrum

high quality Chinese CaF2 optics transmission spectrum

Customized large size and special shape CaF2 optics have good performance at 0.13~10μm wavelength range, a wide range of CaF2 (calcium fluoride) crystal is transparent over a broad range from ultraviolet (uv) to infrared (ir) frequencies.

High quality chinese CaF2 optics is used to manufacture optical components such as windows, drilled discs, and lenses, used in vuv-uv-ir imaging systems, spectroscopy, excimer laser optics, fourier analysis, testing instruments, gas-liquid laser system, astronomical telescope, mir/nir imaging system, etc. Honour optics supplies CaF2 optics for worldwide customers of gas detectors and analyzers. Honour optics is the professional high transmittance laser grade CaF2 optics and vuv, uv and ir grade CaF2 optics manufacturer, welcome to consult purchase plano/spherical/aspherical/cylindrical CaF2 optics optimal price.

Main applications summarized as follows:
Uv to infrared systems
Thermal imaging
Fourier analysis
Testing instruments
Gas-liquid laser system
Astronomical telescope
Mir/nir imaging system
Microlithography
Excimer laser
High energy detection
Large size lenses for laser engraving

Honour optics is the professional manufacturer of CaF2 (calcium fluoride) with rohs environmental protection requirements. Honour optics could provide:
Uvu excimer level, uv and ir level CaF2 (calcium fluoride) optical components with different shapes, such as rod, square, step, wedge, prism, spherical, cylindrical and so on.
CaF2 (calcium fluoride) ir viewport windows for infrared thermography at 8μm to 10μm
Mono or polycrystal, maximum size is about 300mm
Orientation:<100>、<110>、 <111>