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Optical
crystals, such as CaF2, BaF2, MgF2,
LiF, NaCl, KCl, KBr, etc, are widely used in IR optics and UV optics.
High transparency and low loss optical windows, prisms, lenses, achromatic
lenses and parallel planes have been fabricated in these optical materials.
We supply high quality, low cost and large size crystals based on the
Czochralsky and Bridgeman Methods. These crystals are widely applied
to the entire optical wavelength range, from vacuum ultraviolet (0.11
µm) to far infrared (40 µm). MolTech is ready to meet our customers'
various requirements for dimensions and other specifications.
Lithium fluoride (LiF) crystals are well-suitedl
for manufacturing optical elements (mirrors, windows, lenses) for UV,
visible and IR applications. These crystals are optically isotropic,
middle hard, hygroscopic, unsolvable in water.
Magnesium Fluoride (MgF2) is the only
optical material combining wide spectral transmittance band with birefringince
phenomenon and satisfactory thermal expansion coefficient for isotropic
crosssection. It is used for UV-radiation sources and receivers windows
manufacture; for optical elements of interference-polarization filters,
as laser resonator optics elements in quantum electronics and as active
material in IR and submillimeter band .
Calcium Fluoride (CaF2 or Fluorite) crystals
are transparent in wide spectrum band. The product finds use in windows,
lenses operating in UV and IR spectrum band. Laser Use: Calcium Fluoride
is also used as a host lattice for laser crystals. Due to its composition,
CaF2 has a much longer useful life than most materials when
used in fluorine environment.
Barium Fluoride (BaF2) crystals are transparent
in wide spectrum band. The product finds use in windows, lenses of special
types of objectives, as mirrors substrate in optical systems operating
in UV and IR spectrum band. |
Physical
Properties:
| Material |
LiF
|
MgF2
|
CaF2
|
BaF2
|
| Transmission
range (thickness 10 mm), µm |
0.12
- 6.50
|
0.11
- 8.0
|
0.15
- 9.00
|
0.15
- 15.00
|
| Crystal
structure |
cubic
|
tetragonal
|
cubic
|
cubic
|
| Lattice
constant, Å |
a
= 4.026
|
a
= 4.64; c = 3.06
|
a
= 5.462
|
a
= 6.196
|
| Density,
g/cm3 |
2.60
|
3.177
|
3.18
|
4.89
|
| Mohs hardness |
4
|
6
|
4
|
3
|
| Refractive
indexes |
n
= 1.387
|
ne
= 1.3852; no = 1.3796
|
1.6921
- 1.3161
|
n
= 1.4686
|
| Solubility,
g/100 g water at 18°C |
-
|
7.6
x 10-3
|
1.6
x 10-3
|
0.12
|
Specifications
for windows:
| Surface
quality, scratch - dig |
60 - 40 |
| Clear aperture |
90% of
diameter |
| Diameter
tolerance, mm |
+0.0 /
-0.1 |
| Thickness
tolerance, mm |
± 2 |
| Flatness |
»/4
(633 nm) |
| Parallelism,
arc min |
3 |
| ” N |
< 0.5
x 10-5 |
| Optical
losses, cm-1 for MgF2-UV (200 nm) |
< 0.07 |
| Optical
losses, cm-1 for MgF2-UV (500 nm) |
< 0.02 |
| Optical
losses, % for CaF2 (4 µm) |
5.6 (two
surfaces) |
| Optical
losses, cm-1 for BaF2 |
at 0.2
µm
- < 0.20; 0.4 µm - < 0.08; 10.6 µm - < 0.13 |
Lenses and prisms
made from fluorides are available at request.
|