MgF2 (Magnesium Fluoride) Optics and Crystals

Magnesium Fluoride, chemical formula MgF2, of rutile type structure with exceptional comprehensive optical and mechanical properties. The transmission wavelength range of MgF2 crystal from 0.12μm to 7.5μm covers the vacuum UV (VUV), deep UV (DUV), UV, visible, and IR spectra. 

With a combination of advantages like superior optical transmission and low refractive index, magnesium fluoride is a great option for manufacturing optics such as optical lenses, windows, and prisms. Compared with calcium fluoride, MgF2 is distinguished by a shorter cut-off wavelength and better transparency to ultraviolet light, MgF2 crystal, when used as a transmissive optical material, provides high optical transmission for deep UV and vacuum UV wavelengths. The most typical application of MgF2 crystals is UV optical components and excimer laser optics. However, the application range of magnesium fluoride crystal is limited by its mild birefringence, making CaF2 a much more prevalent choice. Nevertheless, its optical birefringence resulting from the anisotropic microstructure of mgf2 crystal can be utilized to make polarization optics, like crystalline birefringent waveplates.

Moreover, MgF2 also exhibits outstanding physical and chemical properties. The merits of magnesium fluoride crystals include excellent mechanical endurance, higher harness than CaF2, and high thermal shock resistance, making them suitable for extreme conditions. MgF2 crystals also possess high chemical inertness and resistance against deep UV radiations, which further increases their versatility. 

Hangzhou Shalom EO offers custom Deep UV and Vacuum UV optics and crystals, this page specifies our magnesium fluoride crystals (available as crystal ingots, blanks, coated or polished) and MgF2 optics, like MgF2 windows, lenses, prisms, waveplates, etc. 

Shalom EO is capable of providing MgF2 crystals with a maximum ingot diameter of 120mm, and high UV transmission (>99%@193nm within the crystal). Standard orientations like (001), (110), (100), or other custom orientations are available. Our magnesium fluoride products also come in multiple grades, where we can offer single crystal MgF2 and polycrystalline MgF2, where the different grades can be used for applications in different spectral ranges including VUV, DUV-UV, VIS-IR. Shalom EO’s MgF2 crystal ingots are grown using a high-purification growing process and the Bridgman-Stockbarger method, contributing to low absorption in the VUV to DUV wavebands and strong DUV irradiation resistance. 

Shalom EO's MgF2 (magnesium fluoride) optics feature strictly maintained precision, leveraging processing techniques like TSK/wire sawing,  fine grinding/fine polishing, surface quality of 10/5 S/D, and surface roughness of <0.5nm at best can be realized. Coating options include anti-reflection coating, high-reflection coating, etc.

Besides the bulk MgF2 crystals, Shalom EO also supplies custom MgF2 optical components, comprising ( Note that magnesium fluoride crystal is a hard crystal and can be polished to high precision.):

• MgF2 Optical Windows: Optical windows are transparent optical components that allow light to pass with minimum distortion and loss while protecting the core optical element. Shalom EO provides a series of MgF2 windows, including flat windows, square windows, stepped windows, and more. The coatings of the windows can be selected, and mgf2 windows of special shapes such as windows with drilled holes, and wedge windows are available. Surface quality of 10/5 S/D, surface flatness of λ/10, and parallelism <10" can be achieved. 
• MgF2 Lenses: Optical lenses are transmissive optical components with special surface profiles that converge or diverge light. Shalom EO supplies plano-convex/concave, double convex/concave, meniscus MgF2 lenses, etc. MgF2 lenses are excellent for laser focusing of various UV lasers (e.g. excimer lasers), and to be used as focusing lenses of ultraviolet photolithography, offering high damage threshold and low optical absorption.
• MgF2 Prisms: right angle prisms, equilateral prisms, Dove prisms, penta prisms, roof prisms. The MgF2 prisms are great for beam steering of UV lasers.
• MgF2 Optical Filters
• Waveplates: We can provide various mgf2 waveplates of different retardation values.
• MgF2 Beam Splitter: Beamsplitters split light into two components according to polarization or splitting ratio.
• Various custom-shaped MgF2 optics: cylindrical lenses, rod lenses, micro lenses, waveguides, etc.

Typical application of MgF2 Crystals and Optics:

• Optical Coatings: MgF2 crystals can be used as AR coatings for optics, where their low refractive index helps reduce Fresnel reflection.
• Excimer Lasers: MgF2 crystals are often used in 193nm excimer lasers, as MgF2 crystals are capable of withstanding high laser energies and providing low optical absorption. 
• Ultraviolet (UV) Optics: With a short cut-off wavelength at 121nm, MgF2 crystals is well-suited for UV optics. It's used in applications like UV semiconductor processing, fluorescence spectroscope, offering excellent transmission in the deep UV region.
• X-ray Lithography: With excellent X-ray transmission and chemical inertness, MgF2 crystal can be used as a mask material in X-ray lithography to realize high-resolution processing of semiconductor on large scale, which are crucial in the production of integrated circuits.
• Scintillators: MgF2 can function as a scintillator for radiation detection applications, including medical imaging and nuclear research.
• Infrared Optics: While MgF2 has limited transmission in the infrared (IR) region due to its wide bandgap, it is still useful in some IR optics applications such as a protective coating or window material, shielding more sensitive infrared components from damage while allowing other wavelengths to pass through.

Transmission Curve of Shalom EO’s MgF2 Crystals: