Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom.
Institut für Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth, Germany.
Phys Rev Lett. 2015 Apr 3;114(13):137401. doi: 10.1103/PhysRevLett.114.137401. Epub 2015 Mar 30.
We demonstrate a new method to realize the population inversion of a single InGaAs/GaAs quantum dot excited by a laser pulse tuned within the neutral exciton phonon sideband. In contrast to the conventional method of inverting a two-level system by performing coherent Rabi oscillation, the inversion is achieved by rapid thermalization of the optically dressed states via incoherent phonon-assisted relaxation. A maximum exciton population of 0.67±0.06 is measured for a laser tuned 0.83 meV to higher energy. Furthermore, the phonon sideband is mapped using a two-color pump-probe technique, with its spectral form and magnitude in very good agreement with the result of path-integral calculations.
我们展示了一种新方法，通过激光脉冲在中性激子声子边带内调谐，实现单个 InGaAs/GaAs 量子点的粒子数反转。与通过相干拉比振荡反转两能级系统的传统方法相反，通过非相干声子辅助弛豫使光学修饰态快速热化来实现反转。对于调谐到较高能量的激光，测量到最大激子数为 0.67±0.06。此外，使用双色泵浦-探测技术绘制了声子边带，其谱形和幅度与路径积分计算的结果非常吻合。
