Calcium Fluoride is used for optical windows, lenses and prisms in the 0.15 μm - 9 μm range. This material has found wide use in high power laser optics due to its low absorption. Polished surfaces are stable and will last several years under normal conditions. Due to its low refractive index, Calcium Fluoride can be used without anti-reflection coating.
Calcium fluoride is grown by vacuum Stockbroker technique. Material for IR use is grown using naturally mined fluorite, in large quantities at relatively low cost.

OPTICAL
Transmission Range ...........................0.13 to 10 microns
Refractive Index ...................1.39908 at 5 microns
Reflection Loss ....................4% at 5 microns (2 surfaces)
Restrahlen Peak ..............................................35 microns
dN/dT ..................................-10.6 x 10-6e/°C

PHYSICAL
Density........................... 3.18 g/cm3

Melting Point ..................................1360 °C
Thermal Conductivity .............................9.71 W/(m*K)

Thermal Expansion ..............................18.85 x 10-6e/°C

Hardness Knoop ...................................158.3 kg/mm2 (100)
Specific Heat Capacity .......................... 854J/(kg K)
Dielectric Constant............................ 6.76 at 1MHz
Young's Modulus (E)................................. 75.8 GPa
Shear Modulus (G) ................................33.77 GPa

Bulk Modulus (K) .....................................82.71 GPa
Elastic Coefficients............. C11=164 MPa, C12=53 MPa, C44=33.7 MPa
Apparent Elastic Limit ...................................36.54 MPa
Poisson Ratio .......................................0.26

CHEMICAL
Solubility ........................................0.0017g/100g water at 20 °C
Molecular Weight ..........................................................78.08
Class/Structure ....................................... Cubic(111) cleavage

REFRACTIVE INDEX
................1.51(0.19μm), 1.49(0.21μm), 1.47(0.25μm), 1.45(0.33μm), 1.44(0.41μm) 1.43(0.88μm), 1.42(2.65μm), 1.41(3.90μm), 1.40(5.00μm), 1.38(6.20μm), 1.36(7.00μm), 1.34(8.22μm)

Material: ................................................................CaF2
Dimension Tolerance: .....................................+/-0.1mm
Thickness Tolerance: ......................................+/-0.2mm
Surface Accuracy: .....................................................λ/4
Surface Quality: ....................................................40-20
Parallelism: ...............................................................<1'
Clear Aperture: ....................................................>90%
Bevelling: ........................................................0.2×45°
Coating: .................................................Custom Design

Note: Other sizes and specifications are available upon request.