Lithium Fluoride (LiF)
Lithium Fluoride has high transmittance in the UV region (120nm – 400nm) and is used in a range of components in UV-sources, receivers and eximer lasers. Windows, polarizers and lenses benefit from LiF as a substrate.
Care should be taken with LiF material due to its weakness when exposed to sudden changes in temperature. Non-standard AR coatings are used when coating LiF material.
Roditi’s optical LiF material is single-crystal optical quality, fabricated to order.
Specification
| Substance | Form | Diameter Range | Thickness Range | Transmission Range (µm) | Standard Surface Finish |
|---|---|---|---|---|---|
| Lithium Fluoride | Single Crystal | 5mm – 250mm | 1mm – 100mm | 0.12 – 6.00 | Fine Ground / Optical Polish |
Material Properties
| Transmission Range | 0.12 – 6.0 microns |
| Refractive Index | 1.3920 @ 0.6 microns |
| Reflection Loss | 5.2% @ 0.6 µm (2 surfaces) |
| Absorption Coefficient | 5.9 x 10-3/cm @ 4.3µm |
| Density | 2.64 gm/cc |
| Melting Point | 855°C |
| Poisson Ratio | 0.324 (calculated) |
| Hardness | 102 Knoop, approx. 3. – 3.5 Mohs |
| Crystal Structure | Cubic <100> cleavage plane |
| Thermal Expansion Coefficient | 37 x 10-6/K |
