Refractive index database

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Optical constants of MgF2 (Magnesium fluoride)
Zheng et al. 2023: n(e) 0.22–1.7 µm; 368 °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: 367.9 °C


Extraordinary ray (e). 367.9 °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]


Magnesium fluoride, MgF2

Magnesium fluoride (MgF2) is a transparent crystalline material known for its outstanding transmission properties in the ultraviolet to infrared spectrum. It is birefringent and often used in optical components such as windows, lenses, prisms, and polarizers. MgF2 is commonly applied as a protective antireflection coating on optical elements due to its high laser damage threshold, making it especially valuable for applications involving intense ultraviolet light, like those in excimer lasers. Its resistance to mechanical and thermal shocks, coupled with its transparency, also makes it suitable for use in rugged environments and outer space applications.

Other names

  • Magnesium difluoride
  • Magnesium(II) fluoride

External links