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CaF₂ Crystal

Calcium fluoride (CaF2) crystal is transparent across a wide wavelength range from the vacuum ultraviolet (VUV) to infrared (IR), 0.13 to 11µm; the refractive index of CaF2 crystal is lower than that of most optical materials, resulting in lower surface reflection without the need for coating; it demonstrates low dispersion and low stress birefringence, and can be produced in large sizes. Furthermore, CaF2 is chemically stable and insoluble in water. These characteristics collectively make CaF2 crystal an excellent choice for the fabrication of UV lenses, IR lenses, telescope lenses and other multispectral optics.

Features of CaF2 Crystal

- Transparent from VUV to IR, 0.13 to 11µm;
- Low refractive index, resulting in lower surface reflection without the need for AR coating;
- Low dispersion, low stress birefringence;
- Large size available;
- Chemically stable and insoluble in water;

Applications of CaF2 Crystal

- Industry standard material for excimer laser optics in projection and illumination optical designs for the microlithography process.
- Multispectral optical materials for a wide spectrum of applications
- Optics for astronomical instrumentation
- Thermal imaging instrument
- Europium doped CaF2 is used as gamma-ray scintillator

CaF2 Crystal Properties

Class/Structure:

Cubic, Space group Fm3m, (111) cleavage

Lattice Parameter:

a= 5.462 Angstroms, z=4

Density :

3.18 g/cm³

Melting Point :

1360~1423°C

Hardness :

Knoop 158.3 (100) with 500g indenter

Elastic Coefficients :

C11 = 164 C12 = 53 C44 = 33.7

Youngs Modulus (E) :

75.8 GPa

Shear Modulus (G) :

33.77 GPa

Bulk Modulus (K) :

82.71 GPa

Apparent Elastic Limit :

36.54 MPa

Poisson Ratio :

0.26

Solubility :

0.0017g/100g water at 20°C

Molecular Weight :

78.08

Thermal Conductivity :

9.71 W /m /K

Thermal Expansion :

18.85 x 10^-6/°C

Specific Heat Capacity :

854 J /Kg-K

Dielectric Constant :

6.76 at 1MHz

Refractive Index :

1.39908 at 5 µm

Reflection Loss :

5.4% at 5 µm

Absorption Coefficient :

7.8 x 10^-4 /cm @ 2.7 µm

Reststrahlen Peak :

35 µm

dn/dT :

-10.6 x 10^-6/°C

dn/dμ :

0 : 1.7 µm

Transmission Range :

0.13 to 11 µm

Refractive Index vs Wavelength

λ(μm)	0.19	0.21	0.25	0.33	0.88	2.65	3.90	5.00	7.00	8.22
n	1.51	1.49	1.47	1.45	1.43	1.42	1.41	1.40	1.38	1.36

Order CaF2 Crystal

OptoCity offer CaF2 crystal and CaF2 products include: CaF2 Lenses, CaF2 Windows, CaF2 Optical Beamsplitters, CaF2 Optical Filters, CaF2 Wedges, CaF2 Prisms. Please send us an email to request for quote.

Lithium, magnesium, and barium fluorides (LiF, MgF2 and BaF2) are also available at Optocity

General Specifications

Size:	Diameter up to 300mm (IR grade) Diameter up to 100mm (UV grade)
Inclusion	None visible
Dimension tolerance	+/-0.1mm
Oriential tolerance	6 arc minutes
Surface Quality	20/10
Parallelism	20 arc seconds
Perpendicularity	10 arc minutes
Flatness	λ/8 @ 632.8nm

i. CaF2 Crystal Windows

ii. CaF2 Plano-convex Lenses

Request CAF2 for Quote:

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CaF2 Crystal