Fused Silica Optics Co.,LTD
Fused Silica Optics Co.,Ltd
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Custom Magnesium Fluoride(MgF2) Optical Glass Windows,MgF2 Optics
Magnesium Fluoride(MgF2 window) is used for optical elements in the infrared where extreme ruggedness and durability is required. Its useful transmission range is 0.11 μm - 8.5 μm. Irradiation does not lead to color centers. Magnesium fluoride is a rugged, hard material which is resistant to thermal and mechanical shock. Considerable mechanical shock is needed to cause cleavage. So high purity and polish is extremely critical during processing.
Specifications
| Diameter | 0.2-300mm |
| Diameter tolerance | +/-0.1mm or +/-0.02mm |
| Thickness | 0.10-100mm |
| Thickness tolerance | ± 0.1mm or +/-0.02mm |
| Surface quality (scratch & dig) | 60/40, 40/20 or better |
| Surface accuracy | λ/10, λ/2, λ |
| Clear Aperture | >85%, >90% |
| Parallelism | +/-3' ,+/-30'' |
| Bevel | 0.1~0.3mm×45 degree |
| coating | AR, HR or upon customer request( UV, VIS, IR) |
MgF2 crystal shows good optical and thermal-mechanical properties. It is widely used for optical elements such as windows, lenses and prisms in the ultraviolet and infrared optical system where extreme durability is required. Its useful transmission range is 0.11μm~7.5μm. Because of its birefringence caused by optical anisotropy, MgF2 is also used as polarization optics.
Optical properties
| Transmission Range | 0.11 to 7 microns |
| Refractive Index (table below) | 1.37608 at 0.7 microns |
| Reflection Loss | 5.2% at 0.6 microns (2 surfaces) |
| Absorption Coefficient | 40 x 10-3 cm-1 at 2.7nm |
| Restrahlen Peak | 20nm |
| dN/dT | 2.3 (parallel) & 1.7 x 10-6 (perp) at 0.4nm |
| dN/d | 1.4nm |
Physical properties
| Density | 3.18 gm/cm3 |
| Melting Point | 1255oC |
| Thermal Conductivity | 0.3 Wm-1K-1 at 300K |
| Thermal Expansion | 13.7 (para) & 8.9 (perp) x 10-6/K |
| Hardness | Knoop 415 |
| Specific Heat Capacity | 1003 J Kgm-1K-1 |
| Dielectric Constant | 4.87 (para) 5.45 (perp) at 1MHz |
| Youngs Modulus (E) | 138.5 GPa |
| Shear Modulus (G) | 54.66 GPa |
| Bulk Modulus (K) | 101.32 GPa |
| Elastic Coefficient | C11=140 C12=89 C44=57 C13=63 C66=96 |
| Apparent Elastic Limit | 49.6 MPa (7200 psi) |
| Poisson Ratio | 0.276 |
Chemical properties
| Solubility | 0.0002g/100g water |
| Molecular Weight | 62.32 |
| Class/Structure | Tetragonal, can cleave on C-axis |