Modification of transparent materials by tightly focused annular, radially and azimuthally polarized ultrafast laser beams

Recently, strong longitudinal electric fields have raised great interest in the laser fabrication, microscopy and optical data storage [1]. Here we demonstrate high quality cylindrically polarized annular beam produced by ultrafast laser written spatially variant polarization converter. We observed that nanogratings cannot be formed by strong longitudinal electric fields, created by a ring-shaped radially polarized beam. In addition, the stronger transverse electric field of azimuthal polarization is demonstrated to produce larger retardance.