Rochon & Wollaston PolarisersThe Wollaston and Rochon polarizers are both beam splitting type devices which rely upon the large birefringence of calcite to cause a difference in the refraction angle at the interface between two differently orientated prisms. In both the Wollaston and the Rochon polarizer the prisms are usually cemented at the interface so the optical power handling is low as a result.
WOLLASTON TYPEWollaston prism polarizing beam splitters consist of two equal angle calcite prisms optically coupled with optic axis orthogonally crossed to the direction of propogation. The beam separation of about 20░ is then approximately balanced about the input beam axis. The transmission range for cemented prisms of 0.32 to 2.5Ám to 18░ at 2.5Ám.
ROCHON TYPEIn the Rochon polarizer one polarization state is transmitted undeviated through the prism while the orthogonal component is deviated approximately 10░. The straight through component is clearly chromatic while the deviated beam varies from 11░ at 0.32Ám to 8.5░ at 2.5Ám.
|Wollaston Type BSW||Rochon Type BSR|
Both varieties can be made from optically contacted quartz. The beam deviation is then reduced to only 1░ and 0.5░ respectively because of the much lower birefringence of quartz compared to calcite. However, the spectral range is increased to 0.2 - 2.0Ám.