Lettner Thomas, Gyger Samuel, Zeuner Katharina D, Schweickert Lucas, Steinhauer Stephan, Reuterskiöld Hedlund Carl, Stroj Sandra, Rastelli Armando, Hammar Mattias, Trotta Rinaldo, Jöns Klaus D, Zwiller Val
Department of Applied Physics, KTH Royal Institute of Technology, Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden.
Department of Electrical Engineering, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden.
Nano Lett. 2021 Dec 22;21(24):10501-10506. doi: 10.1021/acs.nanolett.1c04024. Epub 2021 Dec 13.
Entangled photon generation at 1550 nm in the telecom C-band is of critical importance as it enables the realization of quantum communication protocols over long distance using deployed telecommunication infrastructure. InAs epitaxial quantum dots have recently enabled on-demand generation of entangled photons in this wavelength range. However, time-dependent state evolution, caused by the fine-structure splitting, currently limits the fidelity to a specific entangled state. Here, we show fine-structure suppression for InAs quantum dots using micromachined piezoelectric actuators and demonstrate generation of highly entangled photons at 1550 nm. At the lowest fine-structure setting, we obtain a maximum fidelity of 90.0 ± 2.7% (concurrence of 87.5 ± 3.1%). The concurrence remains high also for moderate (weak) temporal filtering, with values close to 80% (50%), corresponding to 30% (80%) of collected photons, respectively. The presented fine-structure control opens the way for exploiting entangled photons from quantum dots in fiber-based quantum communication protocols.
在电信C波段1550纳米处产生纠缠光子至关重要，因为这能够利用已部署的电信基础设施实现长距离量子通信协议。近来，铟砷外延量子点已能够在该波长范围内按需产生纠缠光子。然而，由精细结构分裂引起的随时间变化的状态演化目前将保真度限制在特定的纠缠态。在此，我们展示了使用微机械压电致动器对铟砷量子点的精细结构抑制，并演示了在1550纳米处产生高度纠缠光子。在最低精细结构设置下，我们获得了90.0±2.7%的最大保真度（并发度为87.5±3.1%）。对于适度（弱）的时间滤波，并发度也保持较高，值分别接近80%（50%），分别对应于30%（80%）的收集光子。所展示的精细结构控制为在基于光纤的量子通信协议中利用来自量子点的纠缠光子开辟了道路。
