Servo study of radially polarized beam in high numerical aperture optical data storage system

In this paper, we employed full vector diffraction treatment to study the dependence of the servo signals to the doughnutshaped focus radiation of radial polarization, which provides a smaller spot size than linear polarization, and the resistance to the primary aberrations in a numerical aperture (NA) = 1.0 optical data storage system. Compared with linear polarization, at strong focusing, a radially polarized beam leads to 14% asymmetry reduction in the linear range of the focus-error signal (FES) curve and to at least 56% variation reduction in crosstalk in a weakly aberrated system. These characteristics make radial polarization a potential candidate for next-generation high-density optical systems.