LiF Window

Lithium Fluoride(LiF) is used for windows, lenses and prisms in the Vacuum UV, UV, visible and infrared where transmission in the range 0.104µm to 7µm is desired. Transmission is about 40% at 121nm. 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.

Advantages

1 ) Excellent optical performance

2 ) Ideal for Applications Ranging from 120nm – 6μm

3 ) Good transmission in the VUV region

Specifications

1 ) Diameter Tolerance: +/-0.2mm

2 ) Thickness Tolerance: +/-0.03mm

3 ) Aperture: >90%

4 ) Surface Quality: 80/50~10/5 (S/D)

5 ) Parallelism: <1 arc minute

6 ) Chamfer: 0.3-0.5mmx45°

Optical Properties

Transmission Range

0.12 to 6 micron

Refractive Index

1.392 at 0.6 micron

Refractive Loss

5.2% at 0.6 micron

Crystal/Class Structure

Cubic FCC, NaCl, Fm3m

Cleavage Plane

(100) cleavage

Thermal Properties

Thermal Expansion

37×10-6 K-1 at 283K

Thermal Conductivity

58.61 W m-1K-1 at 293K

Melting Point

936 ℃

Specific Heat Capacity

310 J Kg-1K-1

Mechanical Properties

Density

5.33 g/cc

Hardness(Knoop)

102 with 600g indenter

Youngs Modulus

64.97 GPa

Shear Modulus

55.14 GPa

Bulk  Modulus

62.03 GPa

Poisson Ratio

0.326

Elastic Limit

11.2 Mpa (1620psi)

Molecular Weight

25.94

Chemical Properties

Solubility

0.27g/100g water at 20℃

Technical Images