Perfect Higher-Order Poincare Sphere Beams from Digitalized Geometric Phases

For a conventional higher-order Poincare (HOP) sphere beam that generalizes optical vortices and vector beams, its donutlike intensity profile varies significantly with topological charges, which is undesirable for many applications in optical manipulations and communications. Recently, the perfect optical vortex and perfect vector beam have been reported to provide a solution. Until now, this strategy has not been extended to the whole HOP sphere. In this work, the concept of a perfect HOP sphere is proposed for the first time and realized by digitalizing the spiral geometric phase with specific structures of circular Dammann gratings (CDGs), which are demonstrated in liquid crystals through dynamic photo-patterning. Via selecting the incident spin, any point on the perfect HOP sphere can be obtained. Properly programming CDGs makes both single-and multi-ringed perfect HOP sphere beams achievable with merits of high efficiency and uniform energy distribution. All experimental results are qualitatively consistent with the theoretical calculations. This integrated liquid crystal device paves the way for perfect optical angular momentum manipulation and facilitates numerous cutting-edge applications.