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Magnesium Fluoride MgF2 optical material reference for UV windows and birefringent optical components

Magnesium Fluoride (MgF2)

Magnesium Fluoride (MgF2) optical material for UV to IR use, with ordinary and extraordinary refractive-index references for engineering review.

Key Properties

Primary engineering references for material screening, packaging review, and RFQ preparation.

Transmission Range
0.12 - 9 um
Refractive Index
no=1.3785 / ne=1.3903 at 0.55 um
Density
3.177 g/cm3
Knoop Hardness
415 kg/mm2
Young's Modulus
138.5 GPa
Thermal Expansion
13.7 parallel c / 8.9 perpendicular c x 10^-6 /K @373 K

About Magnesium Fluoride (MgF2)

Overview

Magnesium Fluoride (MgF2) is often selected when broad spectral coverage, low refractive index, and birefringent behavior must all be considered in the same design review. For practical engineering use, the ordinary and extraordinary rays should be treated separately whenever polarization or crystal orientation matters.

Key Material Reference

ParameterReference
Practical Transmission Guidance0.12-9.0 µm
Local RII Dataset Range0.14-7.5 µm
Reference DatasetLi formula 1, 293 K, ordinary and extraordinary rays
Refractive Indexno=1.3785 / ne=1.3903 at 0.55 µm
Density3.177 g/cm3
Knoop Hardness415 kg/mm2
Young's Modulus138.5 GPa
Thermal Expansion13.7 parallel c / 8.9 perpendicular c x 10^-6 /K @373 K

Selected Refractive Index Reference

The values below are practical references from the local RII dataset at 293 K. Final crystal orientation and polarization-sensitive designs should always use the confirmed ray path and optic axis requirement.

Wavelength (µm)Ordinary noExtraordinary ne
0.2001.42321.4368
0.3001.39311.4056
0.5501.37851.3903
1.0001.37371.3853
3.0001.36191.3725
5.0001.34011.3488

Typical Applications

  • UV windows and protective optics
  • Broadband windows for laboratory systems
  • Birefringent and polarization-sensitive optics
  • Laser optics and alignment components

Engineering Notes

MgF2 should not be treated as an isotropic drop-in material when crystal orientation matters. Engineers should confirm ray direction, polarization sensitivity, coating target, and use environment before releasing the drawing. Compare other candidate substrates through the materials index and the available manufacturing routes under products if the design might also fit CaF2 or LiF.

Procurement Checklist

  • State whether the optic is orientation-sensitive or whether birefringence is not critical for the application.
  • Include wavelength band, dimensions, quantity, and coating target in the RFQ.
  • Call out any UV durability, laser use, or environmental requirement that changes inspection scope.
  • Confirm whether the request is for a substrate blank, finished window, or design-for-manufacture review.

Request Engineering Review

Send wavelength band, dimensions, quantity, coating target, and orientation notes through the contact page for a practical MgF2 review.

Material Properties

Material
Magnesium Fluoride (MgF2)
Practical Transmission Guidance
0.12-9.0 um
Local Dataset Range
0.14-7.5 um
Reference Dataset
Li formula 1, local RII database
Reference Temperature
293 K
Refractive Index
no=1.3785 / ne=1.3903 at 0.55 um
Density
3.177 g/cm3
Knoop Hardness
415 kg/mm2
Young's Modulus
138.5 GPa
Thermal Expansion
13.7 parallel c / 8.9 perpendicular c x 10^-6 /K @373 K

Common Applications

UV windowsBroadband windowsBirefringent opticsLaser opticsPolarization-sensitive components