GLASS / CALCITE ROCHON
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 polished entrance 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 a 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. The useable range of this polarizer is from 350 to 2300 nm.
Specifications:
A grade calcite: quarter to one wave wavefront deformation @ 633 nm due to striae only
S grade calcite: quarter-wave wavefront deformation @ 633 nm due to striae only
Surface flatness: at least quarter wave @ 633 nm over the clear aperture
Surface quality: 40-20 scratch dig
Transmission (uncoated): 35-40% at 350 nm, 65-70% at 400 nm, 80-88% at > 500 nm
please visit Anti Reflection Coating page for reflectivity plots of available coatings
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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CALCITE / FK5 ROCHON |
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Catalog Number |
Clear Aperture Diameter (mm) |
Exit Beam Separation @ 600 nm (degrees) |
Mount Dimensions (Inches) |
Remarks | |
|
OD +/- .0025 |
Length +/- .005 |
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| MRA-10- 5 | 10 | 5 | .748 | .750 |
Grade A Extinction 1*10^-5 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| MRS-15-10 | 15 | 10 | .998 | 1.000 | |
| MRS-15-15 | 15 | 15 | .998 | 1.500 | |