Arrays of radially polarized beams – generation and characterization

Beams with spatially non-homogeneous polarization distributions are interesting for many applications, including microscopy, lithography, and plasmonics. Especially, radially polarized beams have attracted attention because of the generation of a significant longitudinal polarization component as a result of tight focusing. On the other hand, there is an increasing interest in parallelization of processes to increase the efficiency. We have designed and implemented a beam splitter based on diffraction which can generate a uniform array of such beams when combined with a commercial radial polarization converter. Having several degrees of freedom in the design of diffractive optical elements means that we can customize the specifications of this array to the problem in hand. Not only the intensity and phase distribution of spots, but also the exact location of each spot can be determined. It is also possible to define an arbitrary pattern for the overall arrangement of spots in the array. This is especially interesting for applications like lithography. In this work we are aiming to use a combination of phase retrieval and polarimetric measurements in order to characterize the quality of each of the spots in the array of radially polarized beams.