Magnesium Fluoride (MgF2)


Magnesium Fluoride (MgF2)

Magnesium Fluoride (MgF2) is a tetragonal positive birefringent crystal, it is a rugged material resistant to chemical etching, laser damage, mechanical and thermal shock. MgF2 offers excellent broadband transmission from the deep-UV to the mid-infrared, DUV transmission makes it ideal for use at the Hydrogen Lyman-alpha line and for UV radiation sources and receivers, as well as excimer laser applications. MgF2 is very rugged and durable, making it useful in high-stress environments. It is commonly used in machine vision, microscopy, and industrial applications.

Material Properties

Index of Refraction (nd)

No (Ordinary) = 1.390 & ne (Extraordinary) = 1.378 @d-line (587.6 nm)

Abbe Number (Vd)

106.22 (Ordinary), 104.86 (Extraordinary)

Thermal Expansion Coefficient (CTE)

13.7x10-6/℃ (Parallel), 8.48x10-6/℃ (Perpendicular)

Thermal Conductivity


Knoop Hardness

415 kg/mm2



Transmission Regions & Applications

Optimum Transmission Range Ideal Applications
200 nm - 6.0 μm Used in machine vision, microscopy, and industrial applications ranging from the UV Windows, Lenses, and Polarizers that Do Not Require Anti-Reflection Coatings


The right graph is transmission curve of uncoated 10mm thick MgF2 substrate


For more in-depth specification data, please view our catalog optics to see our complete selection of optics made from Magnesium Fluoride.