On‐Demand Longitudinal Transformations of Light Beams via an Amplitude‐Phase‐Decoupled Pancharatnam‐Berry Phase Element

作者：Yu Zou, Yanke Li, Jun Yan, Hui Liu, Yuqi Zhang, Yi Zhang, Dandan Wen, Peng Li, Bingyan Wei, Jianlin Zhao, Sheng Liu · 发表于：Laser & Photonics Review · 年份：2025 · DOI：10.1002/lpor.202502167 · 被引用次数：3 · 研究领域：Metamaterials and Metasurfaces Applications、Orbital Angular Momentum in Optics、Liquid Crystal Research Advancements

ABSTRACT To overcome the inherent phase‐only modulation limitation of conventional Pancharatnam‐Berry (PB) phase elements, we propose a checkerboard‐encoded design that enables simultaneous amplitude and phase modulation through PB phase engineering. This single‐element platform directly generates polarization‐rotating beams with continuously varying polarization angles along the propagation axis, eliminating traditional dynamic phase requirements. By strategically combining the proposed element with a liquid crystal q ‐plate and waveplates, we demonstrate on‐demand longitudinal transformations of polarization states and higher‐order Poincaré sphere beams. Significantly, we achieve, for the first time to our knowledge, the controllable propagation‐transformed optical skyrmions over multiple cycles, whose topological textures periodically evolve with propagation distance. This amplitude‐phase decoupling mechanism and the compatible solution for various longitudinal transformations significantly advance the development of a universal theoretical framework for longitudinal manipulation of light beams.