Design of a broadband UV-visible alpha-barium borate polarizer

Until recently, the construction of polarizers for operation below approximately 260 nm were limited to materials such as magnesium fluoride and crystalline quartz. These materials have a much smaller birefringence than calcite, but unlike calcite they have good transmission below 200 nm. These materials are, however, not well suited for Glan-Taylor-type polarizer designs, as they do not produce a large angular separation of the polarized components. A new material, a-barium borate, has recently become available, which transmits to just below 200 nm and has a birefringence that approaches that of calcite. We analyze the performance of various polarizer designs that use this material. Results are presented that compare theory with experimental investigation of a manufactured device.