Refractive index database

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Optical constants of CaF2 (Calcium fluoride)
Zheng et al. 2023: n 0.22–1.7 µm; 21 °C

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula [ i ]


Conditions & Spec sheet

n_is_absolute: false
wavelength_is_vacuum: false
temperature: 21.1 °C


21.1 °C. The supplementary materials of the original publication contain coefficients of the Sellmeier formula for multiple temperatures in the range of 21 °C to 368 °C.


Q. Zheng, X. Wang, D. Thompson. Temperature-dependent optical properties of monocrystalline CaF2, BaF2, and MgF2, Opt. Mater. Express 13, 2380–2391 (2023) (See Supplementary materials)


[Expressions for n]   [CSV - comma separated]   [TXT - tab separated]   [Full database record]


Calcium fluoride, CaF2

Calcium fluoride (CaF2) is an inorganic compound with a cubic crystal structure, exhibiting excellent optical transparency over a wide range of wavelengths, from ultraviolet to infrared. It has a low refractive index (approximately 1.43 at 589 nm) and minimal chromatic dispersion, making it a preferred material for lenses, optical windows, and other components in spectroscopy and high-resolution imaging systems. Due to its low solubility and chemical stability, it is highly resistant to weathering and corrosion, making it suitable for harsh environments. In the realm of laser applications, CaF2 is often used as an optical gain medium when doped with rare-earth ions such as ytterbium or erbium. The compound is synthesized through various methods, including precipitation from aqueous solutions and high-temperature reactions between calcium and fluorine gas. Its excellent optical, thermal, and chemical properties make calcium fluoride a material of considerable interest for a wide variety of optical and industrial applications.

Other names

  • Calcium difluoride
  • Calcium(II) fluoride


  • Fluorite (fluorspar)

External links