Calcium Fluoride, Calcium Fluoride transmission, CaF2

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. Maximum available size: 320 mm Dia x 60 mm Thk.

Chemical Formula	CaF₂
Crystal Class	Cubic, cleaves [111] plane
Lattice Constant, Å	5.46
Density, g/cm³ (20 °C)	3.18
Molecular Weight	78.08
Dielectric Constant for 105 Hz	6.76
Melting Temperature, K	1630
Thermal Conductivity, W/(m K) at 273 K	10
Thermal Expansion, 1/K at 300 K	18.9 x 10^-6
Specific Heat, cal/(g K) at 273 K	0.204
Debye Temperature, K	510
Young's Modulus, GPa	75.79
Rupture Modulus, GPa	0.0365
Shear Modulus, GPa	33.76
Bulk Modulus, GPa	83.03
Poisson's Ratio	0.28
Knoop Hardness, kg/mm²	178 [100], 160 [110]

Wavelength, µm	0.19	0.21	0.25	0.33	0.41	0.88	2.65	3.90	5.00	6.20	7.00	8.22
Refractive Index	1.51	1.49	1.47	1.45	1.44	1.43	1.42	1.41	1.40	1.38	1.36	1.34