4)
Materials to which can be used
Any anisotropic material, especially uniaxially ones. Some examples are:
- Uniaxial crystals (KDP, DKDP, BaTiO3, quartz, PZT, calcite,
SiC, etc.)
- Uniaxial polymers
- Liquid crystals
- Mechanically stressed materials (glasses, thin optical films, etc.)
- Biological samples
In the table below you will find the definition of the birefringence
classes:
|
BIREFRINGENCE |
|
Descriptive Term |
Range of Values |
|
Very low |
Less than .006 |
|
Low |
.006 - 014 |
|
Moderate |
.014 - .020 |
|
Moderately high |
.021 - .025 |
|
High |
.025 - .045 |
|
Very high |
.045 - .060 |
|
Extremely high |
.06 or higher |
The following table presents
birefringence data for several materials:
|
Material |
Formula |
Birefringence Δn |
|
beryl |
Be3Al2(SiO3)6 |
-0.045 |
|
calcite |
CaCO3 |
-0.172 |
|
calomel |
Hg2Cl2 |
+0.683 |
|
ice |
H2O |
+0.014 |
|
lithium niobate |
LiNbO3 |
-0.085 |
|
magnesium fluoride |
MgF2 |
+0.006 |
|
quartz |
SiO2 |
+0.009 |
|
ruby |
Al2O3 |
-0.008 |
|
rutile |
TiO2 |
+0.287 |
|
peridot |
(Mg, Fe)2SiO4 |
-0.036 |
|
sapphire |
Al2O3 |
-0.008 |
|
sodium nitrate |
NaNO3 |
-0.251 |
|
tourmaline |
(complex silicate
) |
-0.031 |
|
zircon, high |
ZrSiO4 |
+0.055 |
|
zircon, low |
ZrSiO4 |
+0.047 |
|
liquid crystals |
|
> 0.1 |
©
http://en.wikipedia.org/wiki/Birefringence
Δn = n3 - n0
|