Simple and High-precision Polarization Rotation Measurement Based on a High-order Vector Vortex Beam

Device miniaturization and system integration have become a trend of vortex beam parameter measurement. Polarization rotation measurement is a direction of vortex beam parameter measurement. Typical polarization measurement is implemented by using various optical devices, for instance, beam splitters, polarizers and waveplates, thus leading to complicated system and high cost. Benefiting from the ultra-thin structure, optical metasurface has been an ingenious solution for reducing system complexity and enhancing device miniaturization for polarization rotation measurement. Here, an improved approach upon metasurface for directly measuring the polarization rotation angle of linearly polarized light is proposed and experimentally demonstrated. This measurement method is based on a high-order vector beam which has an azimuthally-dependent polarization distribution. After passing through an analyzer, the intensity pattern of such a vector vortex beam turns into a "gear-like" pattern with 2|ℓ| = 40 petals. By recording the displacement of only two of these petals, the rotation angle of the input linearly polarized light can be obtained with a high-precision. This measurement approach gives the development of high-precision polarization parameters a new route and offers an opportunity to other fields, such as, optical communications and chiral optics, as well as nonlinear optics.