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CaF2
Calcium Fluoride
(CaF2) single crystal is an optical material with high transmittance
in ultraviolet, visible and infrared regions of the spectrum: 0.15
¦Ìm ~ 9 ¦Ìm range. CaF2 is widespread used for optical
windows, lenses and prisms in the IR application; especially pure
grades find useful application in the UV and as UV Eximer (High
power applications) laser windows.
Useful: This material has
found wide use in high power laser optics due to its low absorption;
polished surfaces are stable and will last several years under
normal conditions; due to its low refractive index, CaF2 can be used without anti-reflection coating.
Main Properties
Crystal properties |
Crystal Growth Method |
Vacuum Stockbarger |
Max. Size (mm) |
<250 |
Optical properties |
Transmission range (um) |
0.15~9 |
Reflection Loss, % for two surfaces at 5
¦Ìm |
5.4 |
Absorbance |
1.7¡Á10-4£¨3.8¦Ìm£© |
Refractive Index |
See below |
Wavelength (um) |
Refractive Index (n) |
Wavelength (um) |
Refractive Index (n) |
0.1495 |
1.5800 |
4.0000 |
1.4069 |
0.1612 |
1.5490 |
5.0000 |
1.3990 |
0.2000 |
1.4951 |
6.0000 |
1.3856 |
0.3000 |
1.4540 |
7.0000 |
1.3693 |
0.4000 |
1.4419 |
8.0000 |
1.3498 |
0.5000 |
1.4365 |
9.0000 |
1.3268 |
1.0000 |
1.4289 |
10.0000 |
1.3002 |
2.0000 |
1.4239 |
11.0000 |
1.2676 |
3.0000 |
1.4179 |
12.0000 |
1.2299 |
Transmission Curve |
See below |
|
Crystallographic properties |
Syngony |
Cubic |
Lattice Constant, Angstrom (Å) |
5.462 |
Cleavability |
<111> |
Molecular Weight |
78.08 |
Physical properties |
Density, at 291 K |
3.18g/cm3 |
Hardness, Mohs |
4 |
Dielectric Constant for 105 Hz |
6.76 |
Melting point, ¡ãC |
1360 |
Thermal Conductivity, W/m¡¤K at 36¡ãC |
9.71 |
Thermal Expansion, 1/K |
(16.2 ~ 19.4) ¡Á 10-6 |
Specific Heat Capacity, J/(kg¡¤¡ãC) at 40¡ãC |
887.6 |
Knoop Hardness, kg/mm2 |
178 [100], 160 [110] |
Young's Modulus,
Gpa
<100>
<111> |
146.1
89.9
|
Shear Modulus,
Gpa
<100>
<111> |
47.6
33.8
|
Bulk Modulus, GPa |
82.7 |
Debye Temperature, K |
510 |
Elastic Coefficients |
C11=164, C44=33.7, C12=53 |
Poisson Ratio |
0.26 |
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