China's quantum dot yields 98.3% entangled photon pairs
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- Zhiliang Yuan and his team at the Beijing Academy of Quantum Information Sciences demonstrated that quantum dots can be engineered to consistently generate entangled photon pairs on demand, as reported in Nature Materials.
- Indium‑gallium‑arsenide quantum dot embedded in a micropillar cavity was used, with the cavity’s partially reflective mirrors arranged to tailor the dot’s photonic environment.
- Pulsed laser excitation of the dot produced photon pairs at a 98.3% pair‑generation efficiency, meaning 98.3% of emitted photons occurred in pairs.
- Nonlinear optical crystals traditionally generate photon pairs but can also produce multiple unwanted pairs or none, making output control difficult, a limitation the quantum‑dot approach avoids.
- Single quantum emitter nature of the dot yields photon pairs in a well‑defined optical mode, facilitating integration into quantum devices.
- Ultra‑secure quantum communication networks and high‑resolution imaging are highlighted as potential applications of the reliable entangled‑photon source.
Why it matters: The high‑efficiency, on‑demand source gives quantum‑technology developers a practical, controllable alternative to nonlinear crystals, whose unpredictable outputs make control difficult, thereby lowering system overhead and cost for quantum networks in practice while enabling ultra‑secure communication links and high‑resolution imaging systems.
