Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany.
A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021, Russia.
Phys Rev Lett. 2019 Feb 1;122(4):047403. doi: 10.1103/PhysRevLett.122.047403.
Dark excitons are of fundamental importance for a wide variety of processes in semiconductors but are difficult to investigate using optical techniques due to their weak interaction with light fields. We reveal and characterize dark excitons nonresonantly injected into a semiconductor microcavity structure containing InGaAs/GaAs quantum wells by a gated train of eight 100 fs pulses separated by 13 ns by monitoring their interactions with the bright lower polariton mode. We find a surprisingly long dark exciton lifetime of more than 20 ns, which is longer than the time delay between two consecutive pulses. This creates a memory effect that we clearly observe through the variation of the time-resolved transmission signal. We propose a rate equation model that provides a quantitative agreement with the experimental data.
暗激子对于半导体中的各种过程都具有重要意义，但由于它们与光场的弱相互作用，很难通过光学技术进行研究。我们通过监测它们与亮下极化激元模式的相互作用，揭示并表征了非共振注入到含有 InGaAs/GaAs 量子阱的半导体微腔结构中的暗激子，该结构由门控的 8 个 100fs 脉冲串组成，脉冲间隔为 13ns。我们发现暗激子的寿命惊人地长于 20ns，超过了两个连续脉冲之间的时间延迟。这产生了一种存储效应，我们可以通过时间分辨传输信号的变化清楚地观察到。我们提出了一个速率方程模型，该模型与实验数据定量吻合。
