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Quartz (SiO2) Crystals
Crystalline quartz is a positive
uniaxial crystal. It has moderate birefringence over the broad
transparent range from 200 nm to 2300 nm. The excellent physical,
chemical, and optical properties of crystalline quartz such as high transmittance
in ultraviolet, visible and infrared, the
resistance to moisture, high damage threshold, and resistance to scratch
make it the most favorite material for fabrication of waveplates
and general birefringent plates.
Basic Properties of Quartzal Crystals
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Transparency Range: 200 - 2300 nm |
Transmission Curve |
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Crystal Symmetry: Hexagonal, P3121 |
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Lattice Constants: a=b=4.9133A, c=5.4053A |
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Density: 2.65 g/cm3 |
Therm-Optic Coefficients:
dno/dT= -0.52 x 10-6 /oC
@ 530 nm
dne/dT= -0.63 x 10-6/oC
@ 530 nm |
Damage Threshold ( 10ns, 10Hz)
~ 1GW/cm2 at 1064 nm
~ 500 MW/cm2 qt 532 nm |
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Optical Homogeneity: Δn < 10-6/cm
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Mohs Hardness: 7 |
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Thermal Expansion Coefficients: |
αa = 14 x 10-6/K
ac = 7.6 x 10-6/K
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Linear Absorption Coefficients: α<0.01cm-1 from 300 to 2300 nm |
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Sellmeier Equations:
(λ in µm)
:
no2=2.3573-0.01170λ2+0.01054/λ2+1.3414x10-4/λ4-4.4537x10-7/λ6+5.9236x10-8/λ8
ne2=2.3849-0.01259λ2+0.01079/λ2+1.6518x10-4/λ4-1.9474x10-6/λ6+9.3648x10-8/λ8
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| Wavelength(nm) |
no |
ne |
Birefringence
(Δn=ne-no) |
Walk-off Angle
at 45° |
|
1064 |
1.5341 |
1.5428 |
0.00872 |
-0.325 |
|
800 |
1.5384 |
1.5473 |
0.00891 |
-0.331 |
|
532 |
1.5469 |
1.5561 |
0.00920 |
-0.340 |
|
400 |
1.5577 |
1.5673 |
0.00957 |
-0.351 |
|
355 |
1.5646 |
1.5744 |
0.00982 |
-0.358 |
|
266 |
1.5916 |
1.6024 |
0.01077 |
-0.386 |
Specifications of Quartz
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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