Högele Alexander, Seidl Stefan, Kroner Martin, Karrai Khaled, Warburton Richard J, Gerardot Brian D, Petroff Pierre M
Center for NanoScience, Department für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 Munich, Germany.
Phys Rev Lett. 2004 Nov 19;93(21):217401. doi: 10.1103/PhysRevLett.93.217401. Epub 2004 Nov 18.
We show how the optical properties of a single semiconductor quantum dot can be controlled with a small dc voltage applied to a gate electrode. We find that the transmission spectrum of the neutral exciton exhibits two narrow lines with approximately 2 mueV linewidth. The splitting into two linearly polarized components arises through an exchange interaction within the exciton. The exchange interaction can be turned off by choosing a gate voltage where the dot is occupied with an additional electron. Saturation spectroscopy demonstrates that the neutral exciton behaves as a two-level system. Our experiments show that the remaining problem for manipulating excitonic quantum states in this system is spectral fluctuation on a mueV energy scale.
我们展示了如何通过施加在栅电极上的小直流电压来控制单个半导体量子点的光学性质。我们发现中性激子的透射光谱呈现出两条线宽约为2微电子伏特的窄线。分裂为两个线性偏振分量是通过激子内部的交换相互作用产生的。通过选择量子点被一个额外电子占据时的栅极电压，可以关闭交换相互作用。饱和光谱表明中性激子表现为一个二能级系统。我们的实验表明，在该系统中操纵激子量子态的剩余问题是微电子伏特能量尺度上的光谱波动。
