MgF2 (Magnesium Fluoride)
Magnesium Fluoride transmits well into the VUV region to the hydrogen Lyman-alpha line (121nm) and beyond. Magnesium Fluoride is used mostly for UV optics and is excellent for Excimer laser applications.
Physical and optical properties
| Transmission Range : | 0.12 to 7 μm (1) |
| Refractive Index : | No 1.413 at 0.22 μm (4) |
| Reflection Loss : | 5.7% at 0.22 μm (2 surfaces) |
| Absorption Coefficient : | 40 x 10-3 cm-1 at 2.7 μm |
| Reststrahlen Peak : | 20 μm (1) |
| dn/dT : | 2.3 (para) 1.7 (perp) at 0.4 μm (1) |
| dn/dμ = 0 : | 1.4 μm |
| Density : | 3.18g/cc |
| Melting Point : | 1255°C |
| Thermal Conductivity : | 21 (para) 33.6 (perp) W m-1 K-1 at 300K (3) |
| Thermal Expansion : | 13.7 (para) 8.9 (perp) x 10-6 /K (1) |
| Hardness : | Knoop 415 |
| Specific Heat Capacity : | 1003 J Kg m-1 K-1 |
| Dielectric Constant : | 4.87 (para) 5.45 (perp) at 1MHz (1) |
| Youngs Modulus (E) : | 138 GPa (2) |
| Shear Modulus (G) : | 54.66GPa (2) |
| Bulk Modulus (K) : | 101.32 GPa (2) |
| Elastic Coefficients : | C11=140 C12=89 C44=57 C13=63 C66=96 (2) |
| Apparent Elastic Limit : | 49.6 MPa (7200 psi) |
| Poisson Ratio : | 0.276 (2) |
| Solubility : | 0.0002g/100g water |
| Molecular Weight : | 62.32 |
| Class/Structure : | Tetragonal, can cleave on c-axis |
No = Ordinary Ray Ne = Extraordinary Ray
| µm | No | Ne | µm | No | Ne | µm | No | Ne |
| 0.1137 | 1.7805 | 0.1149 | 1.7420 | 0.1179 | 1.6800 | |||
| 0.1198 | 1.6510 | 0.121 | 1.628 | 1.632 | 0.130 | 1.566 | 1.568 | |
| 0.140 | 1.5095 | 1.523 | 0.150 | 1.480 | 1.494 | 0.160 | 1.461 | 1.475 |
| 0.170 | 1.448 | 1.462 | 0.180 | 1.439 | 1.453 | 0.190 | 1.431 | 1.444 |
| 0.200 | 1.423 | 1.437 | 0.220 | 1.413 | 1.426 | 0.248 | 1.403 | 1.416 |
| 0.257 | 1.401 | 1.414 | 0.266 | 1.399 | 1.412 | 0.280 | 1.396 | 1.409 |
| 0.300 | 1.393 | 1.405 | 0.330 | 1.389 | 1.402 | 0.337 | 1.389 | 1.401 |
| 0.350 | 1.387 | 1.400 | 0.355 | 1.386 | 1.399 | 0.400 | 1.384 | 1.396 |
| 0.546 | 1.379 | 1.390 | 0.700 | 1.376 | 1.388 | 1.087 | 1.373 | 1.385 |
| 1.512 | 1.370 | 1.382 | 2.000 | 1.368 | 1.379 | 2.5 | 1.364 | 1.375 |
| 3.030 | 1.360 | 1.370 | 3.571 | 1.354 | 1.364 | 4.000 | 1.349 | 1.359 |
| 4.546 | 1.341 | 1.350 | 5.000 | 1.334 | 1.343 | 5.556 | 1.324 | 1.332 |
| 6.060 | 1.314 | 1.321 |
Magnesium Fluoride is grown by vacuum Stockbarger technique in ingots of various diameters. Magnesium Fluoride is a tough material and polishes well. Therefore, it can be worked to the highest standards. MgF2 is slightly birefringent and usually supplied with the optic axis cut perpendicular to the window faces.
Tags: MgF2 (Magnesium Fluoride)