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Specifications
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B grade calcite |
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greater than one wave wavefront deformation @ 633 nm due to striae only |
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A grade calcite |
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quarter to one wave wavefront deformation @ 633 nm due to striae only |
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S grade calcite |
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quarter wave wavefront deformation @ 633 nm due to striae only
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E type
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made of S grade calcite but polarizer has beam deviation of one arc minute |
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surface
flatness
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at least quarter wave @ 633 nm over the clear aperture
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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 and longer
wavelengths |
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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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