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Calcite (CaCO3) Crystals
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Calcite crystal is a negative uniaxial crystal well-known for its high
birefringence and transparence in broad region of spectrum. It is the
ideal material for manufacturing various polarizers used in visible-IR
range such as Glan-Taylor polarizers, Glan-Thompson polarizers and Glan
laser polarizers. Recently, calcite plate is also widely used for time
delay compensation between two orthogonally polarized ultrafast pulses. |
Basic Properties of Calcite Crystals
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Transparency Range: 350 - 2300 nm |
Transmission Curve |
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Crystal Symmetry: Trigonal, R3c |
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Lattice Constants: a=b=4,994A, c=17,081A |
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Density: 2.71 g/cm3 |
Damage Threshold ( 10ns, 10Hz)
at 1064 nm - 100 MW/cm2
at 532 nm - 50 MW/cm2 |
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Optical Homogeneity: Δn < 10-6/cm
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Mohs Hardness: 3 |
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Thermal Expansion Coefficients: |
αa = 4.9 x 10-6/K
αc = 25.1 x 10-6/K
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Linear Absorption Coefficients: α<0.01cm-1 from 400 to 700 nm |
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Sellmeier Equations:
(λ
in µm)
:
no2=2.69705
+ 0.0192064/(λ2-0.01820)-0.0151624λ2
ne2=2.18438
+ 0.0087309/(λ2-0.01018)-0.0024411λ2 |
| Wavelength(nm) |
no |
ne |
Birefringence
(Δn=ne-no) |
Walk-off Angle
at 45° |
|
1064 |
1.6423 |
1.4797 |
-0.162 |
5.93 |
|
800 |
1.6487 |
1.4821 |
-0.166 |
6.06 |
|
532 |
1.6629 |
1.4886 |
-0.174 |
6.30 |
|
400 |
1.6823 |
1.4974 |
-0.185 |
6.61 |
|
355 |
1.6951 |
1.5032 |
-0.192 |
6.82 |
|
266 |
1.7497 |
1.5259 |
-0.224 |
7.74 |
Specifications of Calcite Components
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Dimension Tolerance: |
±0.05 mm |
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Wedge Angle Tolerance: |
0.1° |
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Surface Quality:
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20/10 Scratch and Dig
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Optical Axis
Orientation: |
+/-0.5° |
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Parallelism: |
<15 arc sec |
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Perpendicularity: |
<10 arc min |
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Flatness:
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λ/4 @ 632.8 nm |
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Transmission
Wavefront Distortion: |
<λ/4 @632.8 nm |
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AR-coating:
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R<0.3% available upon request |
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