Reconfigurable dual-wavelength quantum skyrmions via liquid-crystal topological defects

Abstract

Quantum optical skyrmions are emerging as robust topological states for encoding information, particularly in regimes where entanglement is fragile. These structured quantum fields combine spin and orbital angular momentum into continuous polarization textures that are resilient to local perturbations. To date, quantum optical skyrmions have been realized only at a single wavelength, either as local single-photon skyrmions or as non-local two-photon skyrmions. We recently demonstrated dual-wavelength quantum optical skyrmions, where both regimes coexist within a single reconfigurable platform. By coupling a non-degenerate entangled photon pair to an electrically tunable liquid-crystal topological defect, we generate wavelength-dependent spin–orbit textures that can be continuously tuned between entangled, heralded, and trivial topologies. We further show that the topological structure is preserved after transmission through a biological sample, highlighting potential for bio-imaging applications. The underlying hybrid state also enables preparation of tripartite GHZ-like entanglement across three degrees of freedom using only two photons.