Spin-Multiplexed Metalens Doublet for Varifocal Vortex Generation and Dynamic OAM Manipulation

Achieving multidimensional light field manipulation within a single compact architecture remains a critical challenge in modern integrated optics. Herein, we experimentally demonstrate a spin-multiplexed vortex-zooming (SMVZ) metalens system based on the Pancharatnam–Berry (PB) phase, enabling synergistic and dynamic control of spin angular momentum (SAM), orbital angular momentum (OAM), and focal length. Switching the incident SAM state reconfigures the metalens doublet between positive–negative and negative–positive modes, simultaneously inverting the output topological charge between ±1. Furthermore, continuous near-diffraction-limited zooming is achieved simply by modulating the axial separation of the metalenses, while preserving the selected SAM-OAM mode. The proposed system exhibits high zoom ratios of 20× and 4× under left-handed (LCP) and right-handed circular polarization (RCP) channels, respectively. As a proof-of-concept, we validate the system’s potential in multiscale edge extraction and size-adaptive dynamic optical tweezing. Overcoming the monofunctional limitations of traditional zooming metalenses, this work establishes a versatile meta-optical platform for developing integrated, multifunctional light field manipulation devices.