Phonon-assisted incoherent excitation of a quantum dot and its emission properties
Phonon-assisted incoherent excitation of a quantum dot and its emission properties
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DOI：
10.1103/physrevb.86.241304
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发表时间：
2012-07
影响因子：
3.7
通讯作者：
S. Weiler;A. Ulhaq;C. Roy;S. M. Ulrich;D. Richter;M. Jetter;S. Hughes;P. Michler
中科院分区：
文献类型：
--
作者：
S. Weiler;A. Ulhaq;C. Roy;S. M. Ulrich;D. Richter;M. Jetter;S. Hughes;P. Michler
我们详细研究了单量子点的声子辅助非相干激发机制。光谱失谐的连续波激光通过声学声子耦合到量子点跃迁，在T=9$K时，相对于严格共振激发，激发效率可达到20$%。对量子点强度的激光频率相关分析清楚地映射了潜在的声学声子浴，并与我们的极化子主方程理论很好地吻合。给出了稳态激子密度(与光致发光成正比)的解析解，它预言了一个由电子-声子散射介导的宽带非相干耦合过程。此外，我们还研究了严格共振激发和声子辅助激发下发射光的相干性质，揭示了窄带触发发射子态初始化对于量子点激子系统作为量子比特的可能应用的重要性。
We present a detailed study of a phonon-assisted incoherent excitation mechanism of single quantum dots. A spectrally detuned continuous-wave laser couples to a quantum dot transition by mediation of acoustic phonons, whereby excitation efficiencies up to 20$%$ with respect to strictly resonant excitation can be achieved at $T=9$ K. Laser-frequency-dependent analysis of the quantum dot intensity distinctly maps the underlying acoustic phonon bath and shows good agreement with our polaron master equation theory. An analytical solution for the steady-state exciton density (which is proportional to the photoluminescence) is introduced which predicts a broadband incoherent coupling process mediated by electron-phonon scattering. Moreover, we investigate the coherence properties of the emitted light with respect to strictly resonant versus phonon-assisted excitation, revealing the importance of narrow band triggered emitter-state initialization for possible applications of a quantum dot exciton system as a qubit.