Plasmonic nanoantenna-mediated quantum dot artificial molecules with engineerable collective stimulated emission and inter-quantum dot quantum-state entanglement

Collective stimulated emission and entangled quantum states can find numerous applications such as high-efficiency quantum emitters, quantum encryption, quantum computing, and quantum sensing. Naturally occurring molecules lack the required spectral properties and offer limited flexibility for structural and spectral engineering at the atomic level. In this paper, we present a platform of plasmonic nanoantenna-mediated quantum-dot (QD) “artificial molecules” with engineerable collective radiation states and quantum state entanglement. Since the energy transfer is mediated by plasmonic currents along nanoantennas, the plasmonic nanoantennas significantly increase the energy transfer distance beyond the Förster resonant energy transfer limit. The plasmonic nanoantennas also provide well-defined directions for energy flow, allowing for the engineerable configuration of interactions between the QDs. By tailoring the antenna configurations, specifically half-wave (λ/2) and full-wave (1λ) resonances—we demonstrate the ability to tune the collective stimulated-emission modes. In addition, we show that quantum entangled multi-exciton states can be generated through stimulated emission in these nanoantenna-mediated QD artificial molecules. We provide a detailed theoretical analysis of the nanoantenna-mediated QD interactions, characterizing the resulting collective stimulated emission and inter-QD quantum state entanglement. These atomic-level engineerable QD artificial molecule platforms can find numerous applications in quantum entangled emitters, integrated quantum communication, quantum, computation, quantum sensing, and metrology.