Schöll Eva, Schweickert Lucas, Hanschke Lukas, Zeuner Katharina D, Sbresny Friedrich, Lettner Thomas, Trivedi Rahul, Reindl Marcus, Covre da Silva Saimon Filipe, Trotta Rinaldo, Finley Jonathan J, Vučković Jelena, Müller Kai, Rastelli Armando, Zwiller Val, Jöns Klaus D
Department of Applied Physics, Royal Institute of Technology, Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden.
Walter Schottky Institut and Department of Electrical and Computer Engineering, Technische Universität München, 85748 Garching, Germany.
Phys Rev Lett. 2020 Dec 4;125(23):233605. doi: 10.1103/PhysRevLett.125.233605.
We investigate the degree of indistinguishability of cascaded photons emitted from a three-level quantum ladder system; in our case the biexciton-exciton cascade of semiconductor quantum dots. For the three-level quantum ladder system we theoretically demonstrate that the indistinguishability is inherently limited for both emitted photons and determined by the ratio of the lifetimes of the excited and intermediate states. We experimentally confirm this finding by comparing the quantum interference visibility of noncascaded emission and cascaded emission from the same semiconductor quantum dot. Quantum optical simulations produce very good agreement with the measurements and allow us to explore a large parameter space. Based on our model, we propose photonic structures to optimize the lifetime ratio and overcome the limited indistinguishability of cascaded photon emission from a three-level quantum ladder system.
我们研究了从三能级量子阶梯系统发射的级联光子的不可区分程度；在我们的案例中是半导体量子点的双激子-激子级联。对于三能级量子阶梯系统，我们从理论上证明，对于发射的两个光子，其不可区分性本质上是有限的，并且由激发态和中间态的寿命之比决定。我们通过比较来自同一半导体量子点的非级联发射和级联发射的量子干涉可见度，实验证实了这一发现。量子光学模拟与测量结果非常吻合，使我们能够探索一个大的参数空间。基于我们的模型，我们提出了光子结构，以优化寿命比并克服三能级量子阶梯系统中级联光子发射的有限不可区分性。
