A Wollaston Polarizing Prism consists of two wedges (crystalline quartz or Iceland spar) joined together with optical contact or glue and having the optical axes directed perpendicular to each other. Two emergent rays have orthogonal polarization and disperse almost symmetrically to the ray falling on the angle, which depends on wavelength and the length-to-aperture ratio. When the length-to-aperture ratio is 1, the angular separation will be about 1 degree for Wollaston prisms made of crystalline quartz, and it will be 4 degrees when the length-to-aperture ratio is 4. For the prisms made of Iceland spar the angular separation will be about 20 degrees when the length to aperture ratio is 1. Due to such a big angular separation there will be strong distortion of an image and transverse chromatic aberration. If it is necessary to have the angular separation more than 20 degrees, it is recommended to use Wollaston prisms with three wedges.
