CASCADED POLARIZING BEAMSPLITTER CUBES IN IMAGING-SYSTEMS

Linear polarization rotation tilt is a form of polarization aberration present in polarizing beamsplitter cubes when they are used in imagin g systems. It is caused by the rotation of the polarizing axis (define d by the plane of incidence at the beamsplitting interface) for off-ax is angles of incidence. This aberration is inherent to the geometry of the cube and is unavoidable, causing beam-routing errors and undesira ble losses. In systems that use two or more polarizing beamsplitter cu bes in succession, the cubes can be oriented to either minimize or max imize the loss, where the maximum loss is five times the minimum loss. This polarization aberration is described and a way to minimize beam- routing errors associated with this aberration in a 4-F optical system is demonstrated.