Calcite
Calcite is a natural crystal that has high birefringence,
wide spectral transmission and availability in reasonably sized
rhombs. It's a negative uniaxial crystals and mostly used as
visible and near IR polarizers.
| Physical and Optical
Properties |
| Transparency Range |
350~2300nm |
| Partical Shape |
Crystalline rhombihedral |
| Density |
2.7 g/cm3 |
| Hygroscopic Susceptibility |
Low susceptibility to moisture
|
| Mohs Hardness |
3 |
| Thermal Expansion Coefficient
|
a a=24.39x10 -6 /k;
a c=5.68x10 -6 /k |
| Crystal Class |
Negative uniaxial with no=na=nb,
ne=nc |
| Refractive index,
birefringence(Δ=ne-no) and walk-off angle at 45°C
(ρ) |
n o =1.6557, n e =1.4852
Δn=-0.1705, ρ= 6.20°@ 630nm |
n o =1.6629,
n e =1.4885
Δn =-0.1705, ρ= 6.20°@ 1300nm
|
| Sellmeier Equation
|
n o 2 =2.69705+0.0192064/(λ2
-0.01820)-0.0151624λ2
n e 2 =2.18438+0.0087309/(λ2 -0.01018)-0.0024411λ2
|
Capabilities:
1) Diameter : max 30~40mm
2) Length: max 25~35mm
3) Surface Quality: better than 20/10 scratch/dig Per MIL-0-13830A
4) Beam Deviation: <3 arc min
5) Optical Axis Orientation: +/-0.5°
6) Flatness: <l /4 @633nm
7) Transimission Wavfront Distortion: < l /2 @633nm
8) Coating: upon customer's specification
Notes
As the susceptibility is low so that it's easy to moisture,it's
difficult to achieve excellent optical quality due to low hardness.
|
