Storage and retrieval of vector beams of light in a multiple-degree-of-freedom quantum memory

TLDR

The full structuration of light in the transverse plane—intensity, phase, and polarization—offers unprecedented capabilities for classical and quantum optics, with special topologies enabling enhanced focusing, data multiplexing, and advanced sensing. The study experimentally demonstrates storage of spatio‑polarization‑patterned beams in an optical memory. The authors generate vectorial vortex modes using a liquid‑crystal cell with a topological‑charge optic‑axis distribution and retrieve them at the single‑photon level, preserving phase and polarization singularities. The memory preserves these singularities, enabling applications in classical data processing and quantum networks where structured states provide rotational invariance.

Abstract

The full structuration of light in the transverse plane, including intensity, phase and polarization, holds the promise of unprecedented capabilities for applications in classical optics as well as in quantum optics and information sciences. Harnessing special topologies can lead to enhanced focusing, data multiplexing or advanced sensing and metrology. Here we experimentally demonstrate the storage of such spatio-polarization-patterned beams into an optical memory. A set of vectorial vortex modes is generated via liquid crystal cell with topological charge in the optic axis distribution, and preservation of the phase and polarization singularities is demonstrated after retrieval, at the single-photon level. The realized multiple-degree-of-freedom memory can find applications in classical data processing but also in quantum network scenarios where structured states have been shown to provide promising attributes, such as rotational invariance.