Lithium Fluoride(LiF)Window
Lithium fluoride (LiF) crystal is also one of the common infrared materials, it has the smallest refractive index in the infrared materials, its transmission spectrum range is 120nm-7000nm, usually used in thermal imaging systems, aerospace optical systems and laser optical systems.
Lithium fluoride (LiF) window is one of the basic optical components in optics, usually used as a protective window for electronic sensors or detectors of the external environment. It is used to separate the two sides of the environment, such as separating the inside of the instrument from the outside, so that the inside and outside of the instrument are isolated from each other, thus protecting the internal devices. And it’s often used for laser systems and infrared systems,such as optical instruments,laser device,optical measurement and inspection ect.
Our company can provide round ,square and rectangular Lithium fluoride (LiF) window with diameters from 2-300mm.and thicknesses from 0.12-60mm (accuracy up to 20-10, 1/10L@633nm),coating AR, BBAR, AF or upon request.
Technical parameters of LiF Window
Dimension | 2-300mm |
Thicknesses | 0.12-60mm |
Dimension tolerance | +0/-0.1mm |
Thickness tolerance | ±0.1mm |
Surface quality (scratch & dig) | 60-40, 40-20, or better |
Surface accuracy | λ/2, λ/4 or better |
Parallelism | 3' ,30'' |
Bevel | 0.1~0.3mm x 45 degree |
Clear aperture | >85%,>90% |
Coating | AR coating or cutom |
Material properties of LiF
| Optical Properties | |
| Transmission Range | 0.11-7μm |
| Transmittance | >94.8%@0.6μm |
| Reflection Loss | 5.2%@0.6μm(both surfaces) |
| Absorption Coefficienet | 5.9×10-3@4.3μm |
| Structure | Cubic Crystal System |
| Cleavage Planes | <100> |
| Physical Properties | |
| Density[g/cm3] | 2.639 |
| Melting Point [℃] | 848 |
| ThermalConductivity [W/(m×K)] | 11.3 @ 314K |
| Thermal Expansion [10-6/K] | 37.0 @ 283K |
| Knoop Hardness [kg/mm2] | 415 |
| Specific Heat Capacity [J/(kg×K)] | 1562 |
| Dielectric Constant | 7.33 @ 1 MHz |
| Young's Modulus (E) [GPa] | 64.79 |
| Shear Modulus(G) [GPa] | 55.14 |
| Bulk modulus(K) [GPa] | 62.03 |
| Poisson Coefficient | 0.22 |
| Chemical Properties | |
| Solubility / g/L | 2.7g @ 20℃ |
| Molecular Weight / g/mol | 25.9394 |
Transmission curve
Lithium fluoride crystals have a wide transmission band (110 to 6,600 nm) and a high transmittance, especially in the vacuum UV band, which is the highest among known materials. Therefore, it is used as an optical material in the ultraviolet band. Lithium fluoride meniscus lenses are popular in many UV and IR applications.
