Measurement of the ultrafast gain recovery in InGaAs/GaAs quantum dots: beyond a mean-field description
Measurement of the ultrafast gain recovery in InGaAs/GaAs quantum dots: beyond a mean-field description
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InGaAs/GaAs 量子点超快增益恢复的测量：超越平均场描述
DOI：
10.1103/physrevb.82.115326
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发表时间：
2010
影响因子：
3.7
通讯作者：
W. Langbein
中科院分区：
文献类型：
--
作者：
P. Borri;V. Cesari;W. Langbein
我们测量了一组电泵浦 InGaAs/GaAs 量子点的基态跃迁的超快增益恢复动力学，这些量子点具有由光学预泵浦脉冲制备的非平衡载流子分布。我们发现，预泵光耗尽后的增益恢复动态比没有预泵时更快，这种效应在低温 (15 K) 下最为明显，但在室温下也可观察到。这一发现与载流子分布的平均场描述不一致，并提供了直接证据表明具有离散载流子数量的微观状态决定了宏观响应。观察到的动力学是由条件恢复产生的，其中内部弛豫速度慢于耗尽提前时间的微态被选择性抑制
We measured the ultrafast gain recovery dynamics of the ground-state transition in an ensemble of electrically pumped InGaAs/GaAs quantum dots having a nonequilibrium carrier distribution prepared by an optical prepump pulse. We find that the gain recovery dynamics after optical depletion by the prepump is faster than without prepump, an effect most pronounced at low temperature (15 K) but observable up to room temperature. This finding is not consistent with a mean-field description of the carrier distribution and gives direct evidence that microstates with discrete carrier numbers determine the macroscopic response. The observed dynamics results from a conditional recovery where microstates with an internal relaxation slower than the depletion lead time are selectively suppressed