Infrared Crystal – Lithium Fluoride Glass
Infrared Crystal — Lithium Fluoride (LiF) Optical Windows & Components
High-transmission lithium fluoride crystal discs and windows (LiF) for infrared optics, spectrometers, and thermal imaging — outstanding transmission across a wide UV–IR range, very low absorption and dispersion, excellent optical clarity and low refractive index for minimal reflection losses.
Description
Lithium fluoride crystals have excellent optical properties. Its transmittance range is 0.11um~7um, and it is used as a window, prism and lens in vacuum ultraviolet, ultraviolet, visible light and infrared optical systems. Due to their lattice structure, LiF crystals can also be used as X-ray diffraction elements.
Key benefits
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Deep-UV capable — excellent transmission well into the deep-UV for spectroscopy and lithography.
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Low dispersion & low index — reduces chromatic aberration in multispectral designs.
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Low intrinsic fluorescence — suitable for high-sensitivity detection and spectroscopy.
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Good optical homogeneity — available in polished optics with low internal defects.
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Custom processing — AR coatings, tight thickness tolerances, bevels, edgework and cleanroom packaging available.
Why choose LiF for UV & IR optics
Choose LiF when deep-UV performance is critical and you require a low-dispersion substrate that minimises signal loss and background fluorescence. It’s widely used in research and OEM instruments for spectroscopy, UV laser delivery and multispectral sensor windows. Note that LiF requires careful packaging and protective mounting compared with more robust oxide glasses.
Typical technical specifications
| Density (g/cm3) | 2.639 |
|---|---|
| Transmittance range (μm) | 0.11~7.0 |
| Reflection loss 0.5μm | 5.3% ( both faces ) |
| Elastic coefficient | C11=97.4,C12=40.4,C44=55.4 |
| Solubility ( 9/100gH20·18°C) | 0.27 |
| Refractive index | 1.3943 (at0.5um ) |
| K-hardness(kg/mm2) | 99.1 (100) |
| Cleavage planes | ( 100) |
| Melting point (°C) | 870 |
Applications & industries
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Deep-UV spectroscopy and photometry
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UV laser windows and beam delivery optics
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Spectrometer windows and high-sensitivity detectors
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Multispectral imaging and scientific instrumentation
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Research labs and OEM photonics equipment
Downloads
Lithium Fluoride Glass— Datasheet (PDF):Lithium Fluoride Glass
FAQ
1.What applications is Lif suited for?
Typical uses include deep-UV spectroscopy, UV laser optics, spectrometer windows, high-sensitivity detectors, and multispectral research optics where best deep-UV throughput and low fluorescence are required.
2.Is CaF₂ hygroscopic or sensitive to environment?
LiF is more sensitive than oxide glasses—it is relatively soft and can degrade with prolonged exposure to moisture or aggressive chemicals. Store and mount LiF with protective sealing or coatings for humid environments.
3.Can LiF optics be AR-coated and super-polished?
Yes — LiF can be polished to high optical quality and receive AR coatings tailored for deep-UV, VIS or IR bands. Coating process and adhesion must be matched to LiF’s surface chemistry; please request coating recommendations for your wavelength and power.
