Perfect Higher-order Poincare Sphere Beams Based On Liquid Crystal Geometric Phase Devices

Conventional higher-order Poincare(HOP)sphere beam generalizes vector beams and optical vortices,whose donutlike intensity pro file varies obviously with topological charges.This characteristic is undesirable for applications in optical communications and manipulations.Recently,the perfect vector beam and perfect optical vortex have been proposed to provide a solution.Until now,this concept has not been developed to the whole HOP sphere.In this work,we propose the concept of a perfect HOP sphere beam for the first time and realize it by digitalizing the spiral geometric phase with designated structures of circular Dammann gratings(CDGs).The devices are demonstrated in liquid crystals by dynamic photo-patterning.Via selecting the incident polarization,any point on the perfect HOP sphere can be generated.Properly programming CDGs makes not only single-but also multi-ringed perfect HOP sphere beams achievable with merits of uniform energy distribution and high efficiency.All experimental results are consistent with the theoretical calculations qualitatively.This integrated liquid crystal device provides new opportunities for the manipulation of perfect optical angular momentum and promotes numerous cutting-edge applications.