Subwavelength diffraction gratings with curved grooves to form cylindrical vector beams of different orders

Abstract

In this work we propose a method to calculate the continuous profile of subwavelength gratings for the formation of vector beams with radial polarization of arbitrary orders, including fractional orders. Also, we derive expressions for the vector of subwavelength grating which transforms a linearly polarized beam into a beam with the radial polarization of an arbitrary order. Also, we determine a relation between a vector of the curved diffraction grating and phase function of the grating. Equations of curves of fast and slow axes of crystal polarizer are found in this work. It is revealed that curve crystal axes have the shape of parabolas and it is also shown that fast and slow axes are perpendicular to each other at each point of space.