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Materials>Crystals>Calcite Crystal |
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| Calcite Crystal | ||||||||||||||
Calcite is a negative
uniaxial crystal that has high birefringence, wide spectral
transmission and availability in reasonably sized rhombs. Although
is a fairly soft crystal and is easily scratched, it is ideal
material used as visible and near IR polarizers, such as Golan
Taylor, Golan Thompson and Golan laser.
AZURE selects carefully the
raw calcite crystals by inspecting them with a cw green laser beam.
We have perfected a number of proprietary processes for cutting, grinding
and polishing good quality optical surfaces for calcite prism. These
skills are evident in the high quality of the finished components,
and enable polarizers to be used with very high peak power lasers. |
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| 1.Basic Properties of Calcite crystals |
| Transparency
Range: 350nm - 2300nm Particle Shape: Crystalline Rhombihedral Density: 2.7 g/cm3 Hygroscopic Susceptibility: low susceptibility to moisture Mohs Hardness: 3 Thermal Expansion Coefficient aa =24.39 x 10-6/K; ac = 5.68 x 10-6/K Crystal Class negative uniaxial with no=na=nb, ne=nc |
 Transparency Curve of Calcite |
| Refractive Indices, Birefringence (Dn = ne - no) and Walk-off Angle at 45 (r): no = 1.6557, ne = 1.4852, Dn = -0.1705, r = 6.20 at 0.63 mm no = 1.6629, ne = 1.4885, Dn = -0.1744, r = 6.32 at 1.30 mm |
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Sellmeier Equation (l in mm): no2 = 2.69705 + 0.0192064/(l2 - 0.01820) - 0.0151624l2 n e2 = 2.18438 + 0.0087309/(l2 - 0.01018) - 0.0024411l2 |
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| 2.Specifications |
Surface Quality |
20/10 Scratch and Dig |
Dimension tolerance |
0.1mm |
Beam Deviation |
<3 arc min. |
Optical axis orientation |
+/-0.5 |
| Flatness | l/4@632.8nm |
| Transmission wavefront distortion | l/2@632.8nm |
| AR-coating | R<0.5% |
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