Description of Lithium Fluoride Crystal Substrates
Lithium Fluoride crystals (LiF) belong to the cubic system. The cleavage plane is the (100) plane. They exhibit defined optical characteristics in the deep ultraviolet range. Given that deep ultraviolet technology has progressed in recent years, Lithium Fluoride crystals are frequently employed for deep ultraviolet applications because of their high transmissivity and short cut‐off wavelengths.

Specifications of Lithium Fluoride Crystal Substrates
Key Performance Parameters
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Crystal structure
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Cubic
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Lattice constant
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4.02 A
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Density
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2.65 (g/cm3)
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Melting point
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884 °C
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Growth method
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Bridgeman
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Mohs hardness
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3 Mohs
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Coefficient of thermal expansion
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3.195 x 10-6/°C//c
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Refractive index
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Nr=1.394; Ne=1.394
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Transmission range
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0.11-6.5 µm
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Standard orientation
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<100>, <110>, <111>
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Standard dimensions
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5x5mm, 10x10mm, Ø1" (25.4mm), Ø4" (100mm)
Or as per customer requirements
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Standard thickness
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0.5mm, 1.0mm, 2.0mm, 5.0mm
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Applications of LiF crystals
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IR and UV windows, prism and substrate
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Polishing
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Single-side or double-side polished
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Surface quality
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Epipolished (Roughness: Ra<5A (5 x 5µm)) Optically polished (Surface quality: 60-40, 40-20 or other)
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Applications of Lithium Fluoride Crystal Substrates
Recent progress in deep ultraviolet technology has prompted the use of Lithium Fluoride crystal substrates. They are employed due to their high transmissivity in the deep ultraviolet region and short cut‐off wavelengths.