A multipair-free source of entangled photons in the solid state

• DOI: 10.48550/arxiv.2203.17077
• Publication Date: 2022-01-01
• Authors: Julia Neuwirth; Francesco Basso B...; Michele B. Rota; Jan-Gabriel Hartel; Marc Sartison; Saimon Filipe Cov...; Klaus D. Jöns; Armando Rastelli; Rinaldo Trotta
• Keywords: Photon entanglement; Density matrix; Single-Photon Source; Degree of coherence; Quantum sensor

Unwanted multiphoton emission commonly reduces the degree of entanglement photons generated by non-classical light sources and, in turn, hampers their exploitation quantum information science and technology. Quantum emitters have potential to overcome this hurdle but, so far, effect on quality has never been addressed detail. Here, we tackle challenge using photon pairs from a resonantly-driven dot comparing state tomography second-order coherence measurements as function excitation power. We observe that relative (absolute) probability is low $p_m= (5.6 \pm 0.6)10^{-4}$ ($p_2= (1.5 0.3)10^{-6}$) at maximum source brightness, values lead negligible entanglement. In stark contrast with probabilistic entangled photons, also demonstrate remain practically unchanged against power for multiple Rabi cycles, despite clearly oscillations measurements. Our results, explained theoretical model develop estimate actual contribution two-photon density matrix, highlight dots can be regarded multipair-free solid state.