Direct generation of massive vector-mode entanglement from a polarization-insensitive optical amplifier

Vectorially structured modes, with spatially inhomogeneous polarization, have attracted widespread attention due to their diverse applications across various physical processes. Entangling these modes holds great potential for advancing quantum optical technologies. In this work, we present a polarization-insensitive amplifier based on the four-wave mixing process, capable of directly generating large numbers of entangled vector vortex (VV) modes. When seeded by vacuum fields, the amplifier simultaneously produces 16 sets of two-mode squeezed vacuum states or continuous-variable entangled states, each containing two VV modes. This work opens avenues for developing quantum information processing that fully harnesses the vectorial nature of optical fields.