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MgF2 Optics

MgF2 (Magnesium Fluoride) is a rugged, hard and positive birefringent crystal which is resistant to thermal and mechanical shock. MgF2 (Magnesium Fluoride) is transparent over an extremely wide range of wavelengths. Windows, lenses, and prisms made of this material can be used over the entire range of wavelengths from 0.11μm to 7.5μm. High quality synthetic VUV grade MgF2 (Magnesium Fluoride) is quite expensive. Low-grade MgF2 is sometimes used in the infrared but it is inferior to CaF2 (Calcium Fluoride). MgF2 (Magnesium Fluoride) is tough and works and polishes well, but it is slightly birefringent and should be cut with the optic axis perpendicular to the plane of the window or lens.

Honour Optics also offers HP (hot-pressed) polycrystalline high efficiency thin-film multilayer MgF2 optics operating at 7-9um, which is mainly used as a mid-infrared wave window material. It is used to produce mid-infrared wave vector dome. With high infrared transmittance, small thermal expansion coefficient, good mechanical property, and low preparation cost, it is the best material for mid-infrared wave vector dome. At present Honour offers dome less than Dia. 270mm x 85mm x 10mm, and Plate less than Dia.360mm x 15mm. Honour Optics is the professional VUV, UV and IR grade MgF2 optics manufacturer, welcome to consult the price of wholesale MgF2 optics. Welcome everyone to purchase large size laser grade MgF2 optics.

MgF2 (Magnesium Fluoride) has good mechanical properties, chemical stability, impact resistance, great anti-thermal fluctuations, and radiation. It is also a positive birefringent crystal with high optical transmittance from the vacuum ultraviolet 0.11um to the infrared spectrum 7.5um, suitable for optical lenses, wedge, and window manufacturing. MgF2 is also considered as durable material in deep UV and LWIR application

high efficiency thin-film multilayer MgF2 optics are similar to Calcium Fluoride in its resistance to water. The MgF2 windows are sensitive to thermal shock but do not leave. Irradiation does not lead to color centers.

MgF2 birefringence should be taken into consideration before selection of this material in optical design. It is resistant to thermal and mechanical shock. It is twice as hard as CaF2 but only half as hard as Ge. It is significantly more expensive than CaF2 and BaF2, but usually not more expensive than LiF. MgF2 is diamond turnable.

Products manufactured: Lenses, Aspheric lenses, Windows, Optical Beamsplitters, Optical Filters, Wedges, Prisms.

Surface finish: Polishes of 10-5, or 20-10 scratch-dig are achieved at extra costs respectively mainly for UV applications. Typical specifications for surface quality in the visible and near infrared regions are a 40-20 and 60-40 scratch-dig in the 3 to the 7μm range.

Surface figure: In the UV and Visible spectral regions, surface figure ranges from 1/10 wave to 1/2 wave @0.6328μm. In the infrared, typically required surface figure ranges from 1/2 wave to 2 waves @0.6328μm and is specified depending on the system performance requirements.

AR coating options: Magnesium Fluoride can be AR coated for use in the infrared but generally without much improvement in transmission due to its low index of refraction and already high transmission.

Tab. 1. Main Properties of MgF2

Optical Properties
Transmission Range 110 nm to 7.5 μm
Transmittance >90% at 193 nm to 6 μm
Refractive Index No=1.37608; Ne=1.38771 (at 0.7μm)
Reflection Loss 5.2% at 0.6 μm (both surfaces)
Residual Radiation Peak 20 nm
Absorption Coefficient 0.04 cm-1 at 2.7 μm
dn/dT 2.3 x 10-6 /℃ parallel c-axis

1.7 x 10-6 /℃ perpendicular c-axis

Physical Properties
Density 3.18 g/cm3
Melting Point 1255℃
Thermal Conductivity 0.3 Wm-1K-1 at 300K
Thermal Expansion 13.7 x 10-6 /℃ parallel c-axis

8.9 x 10-6 /℃ perpendicular c-axis

Knoop Hardness 415 with 100g indenter (kg/mm2)
Specific Heat Capacity 1003 J/(kg.k)
Dielectric Constant 1.87  at 1MHz parallel c-axis

1.45  at 1MHz perpendicular c-axis

Youngs Modulus (E) 138.5 GPa
Shear Modulus (G) 54.66 GPa
Bulk Modulus (K) 101.32 GPa
Elastic Coefficient C11=164; C12=53; C44=33.7

C13=63; C66=96

Apparent Elastic Limit 49.6 MPa (7200 psi)
Poisson Ratio 0.276
Chemical Properties
Solubility 0.0002 g/ 100g water at 20℃
Molecular Weight 62.32
Structure Tetragonal Crystal
Cleavage Plane (110)

Tab. 2. Refractive Index of MgF2 crystal

No = Ordinary Ray, Ne = Extraordinary Ray
µm No Ne µm No Ne
0.1198 1.6510  1.655 0.121 1.628 1.632
0.140 1.5095 1.523 0.150 1.480 1.494
0.170 1.448 1.462 0.180 1.439 1.453
0.200 1.423 1.437 0.220 1.413 1.426
0.257 1.401 1.414 0.266 1.399 1.412
0.300 1.393 1.405 0.330 1.389 1.402
0.350 1.387 1.400 0.355 1.386 1.399
0.546 1.379 1.390 0.700 1.376 1.388
1.512 1.370 1.382 2.000 1.368 1.379
3.030 1.360 1.370 3.571 1.354 1.364
4.546 1.341 1.350 5.000 1.334 1.343
6.060 1.314 1.321

Tab. 3. Specification of CaF2 options

Specification Typical Level High precision
Sizes 2mm-150mm 2mm-200mm
Diameter tolerance +/-0.1mm +/-0.05mm
Thickness tolerance +/-0.1mm +/-0.05mm
Surface quality, scr/dig 60/20 10/5
Surface flatness(lambda) L/2 L/10
Parallelism 3 arc min 10 arc sec
Clear Aperture 80% 90%
Chamfer 0.25mm at 45 deg 0.15mm at 45 deg
Coating As requested As requested

Transmission Spectrum 120nm-230nm

MgF2 optics transmission spectrum 120nm 230nm

Transmission Spectrum 200nm-800nm, thickness 10mm

MgF2 optics transmission spectrum 200nm 800nm thickness 10mm

Transmission Spectrum -3

MgF2 optics transmission spectrum

Low-cost plano/spherical/aspherical/cylindrical MgF2 optics is used for optical elements in the infrared where extreme ruggedness and durability is required. The single MgF2 crystal exhibits slight birefringence through its useful transmission range and its birefringence in the infrared could be useful.

Transmits well into the VUV region at the hydrogen Lyman-alpha line (121nm) and beyond. It is also used for most UV optics and is excellent for excimer laser application. Honour Optics is the professional VUV, UV and IR grade MgF2 optics manufacturer, welcome to consult the price of wholesale MgF2 optics. Welcome everyone to purchase large size laser grade MgF2 optics.

Low-cost plano/spherical/aspherical/cylindrical MgF2 optics is used for optical elements in the infrared where extreme ruggedness and durability is required. The single MgF2 crystal exhibits slight birefringence through its useful transmission range and its birefringence in the infrared could be useful.
Honour Optics is the professional manufacturer of MgF2 (Magnesium Fluoride) with ROHS environmental protection requirements. Honour Optics could provide:
UVU excimer level, UV and IR level MgF2 (Magnesium Fluoride) optical components with different shapes, such as rod, square, step, wedge, prism, spherical, cylindrical and so on.
Mono or poly crystal, maximum size is about 200mm
Orientation:<001>, <100>, <110>, <111>, <210>