Transformation of Gaussian to uniform or annular beams by a radial birefringent filter

摘要

The radial birefringent filter for shaping a Gaussian profile to uniform or annular beams has been designed and simulated. It consists of a radial birefringent lens sandwiched between two polarizers. Through designing the three essential parameters, the Gaussian beams can be transformed into uniform or annular beams. Certainly other profiles of the out beams can be obtained just by rotating either of the polarizers. Its performance properties and its design procedures in laser beam shaping system are studied in detail. Such a filter has advantages that it is relatively simple to construct as it requires no phase changes and low cost replication is possible, but one inherent disadvantage of it is its energy loss because of the absorption of light in the two polarizers.