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Lithium Fluoride ( LiF )
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Crystal properties
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Crystal Type
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cubic, NaCl type structure
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Transmission Range
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0.12 ... 9 µm
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Refractive Index
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1.37327 @ 2,5 µm
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Reflective Loss
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4.4 % @ 4.0 µm
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Reststrahlen
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25 µm
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Density
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2.63905 g/cm3
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Melting Point
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870; 848 °C
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Molecular Weight
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25.9394
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Thermal Conductivity
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4.01 W/(m K)
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Specific Heat
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1562 J/(kg K)
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Thermal Expansion
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37 × 10–6 / K @ 0...100 °C
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Hardness (Knoop)
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102 – 103 (indenter load: 600 g)
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Young’s Modulus
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64.79 GPa
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Shear Modulus
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55.14 GPa
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Bulk Modulus
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62.03 GPa
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Rupture Modulus
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10.8 MPa
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Elastic Coefficient
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C11 = 112
C12 = 45.6
C44 = 3.2 GPa
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Dielectric Constant
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9.0 @ 25 °C, f = 100...109 Hz
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Solubility in Water
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0.28 g / 100 g @ 18 °C
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Crystal Structure
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Single crystal, synthetic
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Cleavage Planes
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(100)
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Standard Diameter
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145 mm, 200 mm
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Application
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X-ray monochromator plates
optical material for DUV applications
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Remarks
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tends to create colour centers
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List of Optical Crystals
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Materials
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Refractive Index
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Transmission
Range (mm)
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Density
(g/cmł)
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Thermal Expansion
Coefficient (10-6/K)
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BK7 glass
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1.5164 (588 nm)
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0.330 – 2.1
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2.51
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7.5
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SF11 glass
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1.78472 (588 nm)
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0.370 – 2.5
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4.74
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6.8
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F2 glass
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1.62004 (588 nm)
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0.420 – 2.0
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3.61
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8.2
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Fused Silica
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1.4858 (308 nm)
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0.185 – 2.5
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2.20
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0.55
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CaF2
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1.399 (5.0 mm)
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0.170 – 7.8
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3.18
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18.85
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BaF2
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1.460 (3.0 um)
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0.15 – 12.0
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4.88
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18.4
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Sapphire
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1.755 (1.0mm)
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0.180 – 4.5
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3.98
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8.4
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Silicon
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3.4179 (10mm)
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1.200 – 7.0
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2.33
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4.15
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Ge
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4.003 (10 mm)
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1.900 – 16
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5.33
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6.1
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ZnSe
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2.40 (10 mm)
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0.630 – 18
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5.27
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7.8
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ZnS
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2.2 (10mm)
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0.380 –14
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4.09
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6.5
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LiF
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1.39 (500 nm)
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0.150 – 5.2
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2.64
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37
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KBr
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1.526 (10 mm)
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0.280 – 22
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2.75
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43
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MgF2
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no = 1.3836 ne = 1.3957 (405 nm)
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0.130 – 7.0
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7.37
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a: 13.7 b: 8.48
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YVO4
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no = 1.9500 ne = 2.1554 (1.3 mm)
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0.400 – 5.0
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4.22
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a: 4.46 b: 11.37
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Calcite
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no = 1.6557 ne = 1.4852 (633 nm)
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0.210 – 2.3
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2.75
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a: 24.39 b: 5.68
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Quartz
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no = 1.5427 ne = 1.5518 (633 nm)
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0.200 – 2.3
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2.65
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7.07
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α-BBO
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no = 1.6749 ne = 1.5555 (532 nm)
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0.190 – 3.5
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3.85
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a: 4.0 c: 36
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LiNbO3
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no = 2.2863 ne = 2.2027 (633 nm)
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0.370 – 4.5
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4.64
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a: 16.7 c: 2.0
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