The prisms produce two beams polarized perpendicular to each other. They are manufactured from high-grade calcite free of striae and bubbles. Foster prisms work from the same principle as a Glan-Thompson prism. They have an additional polished surface with an orientation allowing the reflected beam to exit from the prism.

We offer two versions for the Foster polarizing beamsplitters. One allows for direct exit of the reflected beam at 45°. The other version has a side surface coated with a reflective aluminum which directs the reflected beam to exit the prisms at 90° with respect to the incident beam. By default, the prisms are delivered in a box mount and without antireflection coating.

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