High-Dimensional Light Topologies: Fundamentals and Applications

Light is richer than a simple wave. Beyond frequency and intensity, it carries multiple degrees of freedom — phase, polarization, orbital angular momentum (OAM), and spatial mode structure — that can be independently tailored, multiplexed, and exploited. Over the past two decades, structured light has expanded well beyond Laguerre-Gaussian and Bessel beams to encompass configurations in which these degrees of freedom couple to produce genuinely topological field structures.

It is this topological character — vortex phase singularities, polarization skyrmions, optical Möbius strips, and knotted field lines — that marks the current frontier. Here, “high-dimensional” refers both to the multi-DoF coupling that defines these states and to the large Hilbert spaces they open up for quantum encoding. Their topological protection makes them robust under propagation and perturbation, and rapid progress in spatial light modulators (SLMs), digital micromirror devices (DMDs), metasurfaces, and integrated photonic platforms has turned what were proof-of-principle demonstrations into scalable experimental capability.

This Research Topic brings together contributions that bridge foundational theory, experimental realization, and real-world application of high-dimensional topological light fields. Topics of interest include, but are not limited to:

• Orbital angular momentum states and vortex beams in classical and quantum regimes
• Vector vortex beams and spatially variant polarization fields
• Topological invariants, geometric phases, and Pancharatnam-Berry optics
• High-dimensional entanglement and quantum state encoding using spatial modes
• Optical skyrmions, Möbius strips, knots, and other exotic topological structures
• Generation and detection with SLMs, DMDs, metasurfaces, and photonic integrated circuits
• Propagation and robustness of topological light in turbulent and complex media
• Applications in optical trapping, super-resolution imaging, and metrology
• OAM-based classical and quantum optical communications
• Non-paraxial and tight-focusing regimes of structured light fields

We welcome contributions from theoreticians and experimentalists across structured light, photonics, quantum optics, and applied optics. The collection aims to map the current state of the art in high-dimensional topological light and to surface the open problems most likely to shape the next decade of the field.