LITHIUM FLUORIDE (LiF) windows

Alkor Technologies manufactures LiF windows, lenses and prisms according to customer's specifications. Maximum size of LiF optics: Diamter 100 mm, thickness 40 mm. Please contact us for more information.

LiF transmission

LiF transmittance. Sample thickness 10mm.

Lithium Fluoride is used for windows, lenses and prisms in the vacuum UV, UV, visible and infrared where transmission in the range 0.104mkm to 7mkm is desired. Modest precautions should be taken against moisture and high energy radiation damage.

LiF is attacked by atmospheric moisture at 400C, and softens at 600C. LiF is sensitive to thermal shock. Irradiation produces color centers. The material can be cleaved along (100) and less commonly (110). Although the optical characteristics are good the structure is not perfect and cleavage is difficult. VUV grade LiF windows are available. This is the best VUV transmitter available.

Main properties:

Chemical Formula	LiF
Crystal Class	Cubic
Lattice Constant, Å	4.03
Molecular Weight	25.94
Density, g/cm³ (20 °C)	2.60
Reflection Loss, % for two surfaces at 4 µm	4.4
Dielectric Constant for 10²-10¹⁰ Hz at 298 K	9.0
Melting Temperature, K	1140
Thermal Conductivity, W/(m K) at 314 K	11.3
Thermal Expansion, 1/K at 300 K	34.4 x 10^-6
Specific Heat, cal/(g K) at 283 K	0.37
Debye Temperature, K	732
Bandgap, eV	13.6
Solubility, g/100 g H₂O at 291 K	0.27
Knoop Hardness, kg/mm²	100
Young's Modulus, GPa	64.77
Apparent Elastic Limit, MPa	11.2
Shear Modulus, GPa	55.12
Bulk Modulus, GPa	62.0
Poisson Ratio	0.326

Refractive index

Wavelength, µm	0.20	0.22	0.24	0.29	0.39	0.60	1.75	2.75	3.40
Refractive Index	1.44	1.43	1.42	1.41	1.40	1.39	1.38	1.37	1.36

Tel: +7(812)3631240

Fax: +7(812)3631239

Email: technologies@alkor.net