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The calcite Rochon
prism polarizer is made of one prism of calcite and the other of FK5
optical glass. These two prisms are cemented together. In a Rochon, one of
the prisms needs to have its optic axis perpendicular to the entrance
polished face which is a fragile plane in calcite. Therefore, instead of
calcite, one of the prisms is made of FK5. The dispersion and
extraordinary refractive index of calcite match reasonably well with those
of FK5 glass; but due to slight mismatch, the beam deviation of the
straight
through beam of light is approximately 4, 8 and 12 arc minutes in 5, 10
and 15 degrees beam separation Rochons respectively. The beam separation
angle is dependent on wavelength. Useable range of this polarizer is from
350 to 2300 nm.
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Specifications
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A grade calcite |
:
quarter to one wave wavefront deformation @ 633 nm due to striae only |
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S grade calcite |
:
quarter wave wavefront deformation @ 633 nm due to striae only
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surface flatness |
:
at least quarter wave @ 633 nm over the clear aperture |
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surface
quality
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:
40-20 scratch dig |
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transmission
( uncoated ) |
: 35-40%
at 350 nm, 65-70% at 400 nm, 80-88% at > 500 nm |
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please visit
Anti Reflection Coating page for reflectivity plots of available
coatings |
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Calcite is a natural mined
crystal . Defects in bulk calcite are characterized by bubbles ( presence
of randomly scattered bubbles vary from relatively large to small sizes and fine
bubble lines), striae ( streaks of sudden variation of refractive index
which can be detected interferometrically ), optical inhomogeneity (
gradual variation of refractive index in bulk material ) and stress
birefringence ( variation of birefringence in bulk material due to
defective growth of the crystal ). These defects cause degradation of
polarization and transmission loss due to scattering and absorption.
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Catalog Number |
Clear Aperture
Diameter (mm) |
Exit
Beam
Separation
@
600 nm
(degrees) |
Mount
Dimensions
( Inches) |
Remarks |
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OD
+/-
.0025
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Length
+/-
.005 |
| MRA-10-
5 |
10 |
5 |
.748 |
.750 |
Grade
A
Extinction
1*10^-5
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| MRA-10-10 |
10 |
10 |
.748 |
.750 |
| MRA-10-15 |
10 |
15 |
.748 |
1.125 |
| MRA-12-
5 |
12 |
5 |
.873 |
.750 |
Grade
A
Extinction
1*10^-5
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| MRA-12-10 |
12 |
10 |
.873 |
.875 |
| MRA-12-15 |
12 |
15 |
.873 |
1.375 |
| MRA-15-
5 |
15 |
5 |
.998 |
1.000 |
Grade
A
Extinction
1*10^-5
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| MRA-15-10 |
15 |
10 |
.998 |
1.000 |
| MRA-15-15 |
15 |
15 |
.998 |
1.500 |
| MRS-10-
5 |
10 |
5 |
.748 |
.750 |
Grade S
Extinction
5*10^-6
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| MRS-10-10 |
10 |
10 |
.748 |
.750 |
| MRS-10-15 |
10 |
15 |
.748 |
1.125 |
| MRS-12-
5 |
12 |
5 |
.873 |
.750 |
Grade S
Extinction
5*10^-6
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| MRS-12-10 |
12 |
10 |
.873 |
.875 |
| MRS-12-15 |
12 |
15 |
.873 |
1.375 |
| MRS-15-
5 |
15 |
5 |
.998 |
1.000 |
Grade S
Extinction
5*10^-6
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| MRS-15-10 |
15 |
10 |
.998 |
1.000 |
| MRS-15-15 |
15 |
15 |
.998 |
1.500 |
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