Magnesium Fluoride (MgF2)
transmits well into the VUV region at the hydrogen Lyman-alpha
line (121nm) and beyond. Application as window, lens, in
most VUV region optics and is excellent for excimer laser
use.
MgF2 is a positive birefringent crystal with high optical
transmittance from the vacuum ultraviolet to the infrared
spectrum region. It is resistant to mechanical and thermal
shock, to radiation, and is chemically stable.
Main Properties
| Crystal
properties |
| Crystal
Growth Method |
Vacuum
Stockbarger |
| Max.
Size (mm) |
<100 |
| Optical
properties |
| Transmission
range (um) |
0.12~7.00 |
| Reflection
Loss, % for two surfaces at 5 μm |
4.8
|
| Refractive
Index |
See
below |
| Wavelength
(um) |
No |
Ne |
Wavelength
(um) |
No |
Ne |
| 0.121 |
1.62750 |
1.63200 |
0.656 |
1.37661 |
1.38835 |
| 0.140 |
1.50950 |
1.52300 |
1.000 |
1.37360 |
1.38521 |
| 0.178 |
1.43975 |
1.45365 |
2.000 |
1.36800 |
1.37922 |
| 0.200 |
1.42309 |
1.43657 |
3.000 |
1.36000 |
1.37060 |
| 0.300 |
1.39298 |
1.40543 |
4.000 |
1.35250 |
1.36220 |
| 0.436 |
1.38203 |
1.39402 |
5.000 |
1.33020 |
1.33930 |
| 0.488 |
1.38016 |
1.39206 |
6.000 |
1.32420 |
1.33150 |
| 0.588 |
1.37770 |
1.38960 |
7.000 |
1.30440 |
1.31010 |
| Transmission
Curve |
See
below |
|
|
|
|
|
|
|
|
| Crystallographic
properties |
| Syngony |
Tetragonal |
| Lattice
Constant, Å |
a=4.64; c=3.06 |
| Cleavability |
(100),(110), imperfect |
| Physical
properties |
| Density,
at 291 K |
3.18g/cm3 |
| Hardness,
Mohs |
6 |
| Dielectric
Constant for 95x103 - 42x106 Hz |
5.45 |
| Melting
point, °C |
1255 |
| Thermal
Conductivity, W/m，K |
3.14 |
Thermal
Expansion, K
Parallel to c-axis (//)
Perpendicular to c-axis (— ) |
14 〜 10-6
8.9 〜 10-6 |
| Bandgap,
eV |
10.8 |
| Knoop
Hardness, kg/mm2 |
415 |
| Young's
Modulus, GPa |
138.5 |
| Shear
Modulus, GPa |
54.66 |
| Bulk
Modulus, GPa |
101.32 |
| Apparent
Elastic Limit, MPa |
49.64 |
| Poisson
Ratio |
0.276 |
| Chemical
properties |
| Solubility
in water at 18°C |
0.0076g (per
100g water) |
| Molecular
Weight |
62.31 |
|
|
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