Abstract: A polarizer is made from pairs of polarizing beam splitting cubes. In every pair, a first cube transmits P-polarized light and reflects S-polarized light. A retarder rotates the transmitted light to become S-polarized. A second cube receives only the reflected light, and redirects it in the direction of the transmitted light. A polarizing filter filters the reflected light, but not the rotated light. Exposing the retarder improves the transmission throughput of the overall polarizer. A stop at the side of the second cube blocks light from entering the first cube of an adjacent pair.