论文标题
两光子激发集限制了从量子发射器纠缠的光子对产生的限制
Two-Photon Excitation Sets Limit to Entangled Photon Pair Generation from Quantum Emitters
论文作者
论文摘要
纠缠的光子对是量子技术中许多新应用的关键。半导体量子点可以用作点播，高度纠缠的光子的来源。对固定的最大纠缠状态的保真度受激子精细结构分裂的限制。这项工作表明，即使缺乏这种分裂，当两光子共振方案中的激发脉冲具有有限的持续时间时，纠缠程度也无法达到统一。纠缠的降解起源于动态诱导的激光脉冲本身引起的激子状态的分裂。因此，在此处探索的设置中，激发过程限制了在光学激发的四级量子发射极中生成的纠缠光子的可实现的并发。
Entangled photon pairs are key to many novel applications in quantum technologies. Semiconductor quantum dots can be used as sources of on-demand, highly entangled photons. The fidelity to a fixed maximally entangled state is limited by the excitonic fine-structure splitting. This work demonstrates that, even if this splitting is absent, the degree of entanglement cannot reach unity when the excitation pulse in a two-photon resonance scheme has a finite duration. The degradation of the entanglement has its origin in a dynamically induced splitting of the exciton states caused by the laser pulse itself. Hence, in the setting explored here, the excitation process limits the achievable concurrence for entangled photons generated in an optically excited four-level quantum emitter.
