Glan-Thompson prisms are formed using two identical calcite prisms with hypotenuses cemented to one another to form a surface that efficiently transmits one polarization state specifically. The prisms have the same optical axis orientation as one another, which is perpendicular to the plane of reflection (the shared hypotenuse). Light that is s-polarized with respect to the reflective hypotenuse experiences the higher ordinary refractive index of calcite. As calcite has a large index difference between extraordinary and ordinary rays, the polarizer has a fairly wide range of acceptance angles that result in transmission of only highly pure s-polarized light. Thus Glan Thompson prisms have a wide usable acceptance angle and are especially well suited for use with diverging and converging beams.

The Glan-Thompson polarizer has a black anodized aluminum housing. The knurled ring at the center of the housing will unscrew to yield a 1.063-20 thread. This thread conveniently screws into Newport's popular rotation stages such as , , , , and to mention a few.