Rochon
The magnesium fluoride Rochon polarizer is made of two prisms of single crystal magnesium fluoride which are optically contacted. A ray at normal incidence to the entrance face travels perpendicular to optic axis of the first prism as shown. For this arrangement, beam separation angle vs wavelength is plotted below. This polarizer can be used over the spectral range of 140 to 6000 nm and has an extinction ratio of at least 10^-3.
We also offer an air spaced version of a 12 mm clear aperture diameter Rochon. It is mounted in a black anodized aluminum cell. Its beam separation angle varies from .67 degree at 140 nm to .36 degree at 6000 nm. Please contact us for more details.
Specifications:
surface flatness : quarter wave @ 633 nm over the clear aperture
surface quality :40-20 scratch dig
transmission ( uncoated ) : at least 80% at 220 nm, at least 85% from 300 to 5500 nm
( polarizer is supplied uncoated - Fresnel reflection per surface is 2.6% at 633 nm )
Magnesium fluoride is a synthetically grown positive ( Ne > No ) uniaxial crystal which has a wide transmission region from 150 nm and lower to at least 6500 nm and higher. Because of it's relatively low birefringence, it is not feasible to fabricate a magnesium fluoride Glan type polarizer. A Karl Lambrecht Corp. made magnesium fluoride Rochon was first tested at the University of Chicago* in 1969.
* Applied Optics / Vol. 8, No. 6 / June 1969
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MAGNESIUM FLUORIDE ROCHON |
|
Catalog Number |
Clear Aperture Diameter in mm |
Angular Separation in degrees |
Mount Dimensions ( Inches) |
|
|
Outside Diameter +/- .0015 |
Length +/- .007 |
|||
| MFRV5 | 5 | 5.4
@ 140 nm
5.1 @ 200 nm 4.6 @ 546 nm |
.498 | 1.375 |
| MFRV9 | 9 | 1.497 | 2.250 | |