Efficient excitation transfer in an LH2-inspired nanoscale stacked ring geometry

Ring geometries of subwavelength-spaced quantum emitters exhibit outstanding radiation properties and are useful for antennas, excitation transport, and storage. Taking inspiration from the oligomeric geometry, in particular by considering only the position and dipole orientations of the bacteriochlorophylls in biological light-harvesting 2 (LH2) complexes of (approximately 6 nm in diameter), we propose and predict highly efficient interlayer excitation transfer, achieving a maximum of 100% transfer for certain choices of dipole orientations in a three-dimensional (3D) concentric stacked ring geometry with C₉ symmetry and a diameter of 400 nm, formed by two-level atoms. Utilizing the quantum optical open system Lindblad master equation approach for estimating the collective dipole dynamics, we demonstrate that, depending on the system parameters, our bio-inspired 3D ring of quantum emitters enables efficient asymmetric excitation transfer between two ring layers, in particular from sparse to dense quantum emitter arrangements. The presented nanoscale geometry is expected to be realizable with diverse physical platforms operating at cryogenic temperatures, where the interacting dipole description remains applicable and, importantly, dominant over environmental decoherence.