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GLAN THOMPSON
BEAM SPLITTING
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The Beam
Splitting Glan Thompson polarizer is made of two cemented prisms of calcite.
It is a modification of Glan Thompson polarizer in the sense that the
totally reflected ordinary polarization is made to exit the polarizer. For
an input beam at normal incidence, the two orthogonally polarized output
beams exit at normal incidence to their respective output faces.
Therefore, the beam separation angle of 37 degrees and 45 degrees in the
two available versions is independent of wavelength. Their length to
aperture ratio is 3.0 : 1 and 2.5 : 1 respectively. There is a slight
mismatch of refractive index of straight through extraordinary beam and
the cement. Due to this, some extraordinary polarization is reflected which
results in unequal extinction ratio of the two output beams. These
polarizers can be used from 350 nm to 2300 nm. The table shown lists A
grade polarizers. Polarizers made of B or S grade of calcite are also
available upon request.
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Specifications
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B grade calcite |
:
greater than one wave wavefront deformation @ 633 nm due to striae only |
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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
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:
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 )
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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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BEAM
SPLITTING GLAN THOMPSON |
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Catalog Number |
Clear Aperture
Diameter (mm) |
Mount
Dimensions
( Inches) |
Remarks |
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Height
Maximum
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Width
+/-
.0025
|
Length
+/-
.005 |
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MSBTB-
8-45 |
8 |
.875 |
.622 |
1.125 |
Grade
B
Extinction
- Reflected Beam 1*10^-4
Extinction
- Straight Through Beam 5*10^-5
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| MSBTB-10-45 |
10 |
1.000 |
.872 |
1.375 |
| MSBTB-12-45 |
12 |
1.125 |
.996 |
1.500 |
| MSBTA-
8-45 |
8 |
.875 |
.622 |
1.125 |
Grade
A
Extinction
- Reflected Beam 5*10^-5
Extinction
- Straight Through Beam 1*10^-5
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MSBTA-10-45 |
10 |
1.000 |
.872 |
1.375 |
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MSBTA-12-45 |
12 |
1.125 |
.996 |
1.500 |
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MSBTS- 8-45 |
8 |
.875 |
.622 |
1.125 |
Grade S
Extinction - Reflected Beam 1*10^-5
Extinction
- Straight Through Beam 5*10^-6 |
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MSBTS-10-45 |
10 |
1.000 |
.872 |
1.375 |
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MSBTS-12-45 |
12 |
1.125 |
.996 |
1.500 |
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MSBTB-
8-37 |
8 |
.875 |
.622 |
1.500 |
Grade
B
Extinction
- Reflected Beam 1*10^-4
Extinction
- Straight Through Beam 5*10^-5
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| MSBTB-10-37 |
10 |
1.000 |
.872 |
1.625 |
| MSBTB-12-37 |
12 |
1.125 |
.996 |
1.875 |
| MSBTA-
8-37 |
8 |
.875 |
.622 |
1.500 |
Grade A
Extinction - Reflected Beam 5*10^-5
Extinction
- Straight Through Beam 1*10^-5 |
| MSBTA-10-37 |
10 |
1.000 |
.872 |
1.625 |
| MSBTS-12-37 |
12 |
1.125 |
.996 |
1.875 |
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MSBTS-
8-37 |
8 |
.875 |
.622 |
1.500 |
Grade S
Extinction - Reflected Beam 1*10^-5
Extinction
- Straight Through Beam 5*10^-6 |
| MSBTS-10-37 |
10 |
1.000 |
.872 |
1.625 |
| MSBTS-12-37 |
12 |
1.125 |
.996 |
1.875 |
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