Technische Physik and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Universität Würzburg, D-97074 Würzburg, Am Hubland, Germany.
Nature. 2013 May 16;497(7449):348-52. doi: 10.1038/nature12036.
Conventional semiconductor laser emission relies on stimulated emission of photons, which sets stringent requirements on the minimum amount of energy necessary for its operation. In comparison, exciton-polaritons in strongly coupled quantum well microcavities can undergo stimulated scattering that promises more energy-efficient generation of coherent light by 'polariton lasers'. Polariton laser operation has been demonstrated in optically pumped semiconductor microcavities at temperatures up to room temperature, and such lasers can outperform their weak-coupling counterparts in that they have a lower threshold density. Even though polariton diodes have been realized, electrically pumped polariton laser operation, which is essential for practical applications, has not been achieved until now. Here we present an electrically pumped polariton laser based on a microcavity containing multiple quantum wells. To prove polariton laser emission unambiguously, we apply a magnetic field and probe the hybrid light-matter nature of the polaritons. Our results represent an important step towards the practical implementation of polaritonic light sources and electrically injected condensates, and can be extended to room-temperature operation using wide-bandgap materials.
传统半导体激光发射依赖于光子的受激辐射，这对其运行所需的最小能量提出了严格的要求。相比之下，强耦合量子阱微腔中的激子极化激元可以经历受激散射，从而有望通过“极化激元激光”更有效地产生相干光。在温度高达室温的光泵浦半导体微腔中已经演示了极化激元激光的运行，并且此类激光器在阈值密度较低的情况下比弱耦合对应物表现更好。尽管已经实现了极化激元二极管，但直到现在，对于实际应用至关重要的电泵浦极化激元激光操作尚未实现。在这里，我们提出了一种基于包含多个量子阱的微腔的电泵浦极化激元激光。为了明确证明极化激元激光发射，我们施加磁场并探测极化激元的光物质混合性质。我们的结果是朝着实现极化激子光源和电注入凝聚态的实际应用迈出的重要一步，并且可以通过使用宽带隙材料扩展到室温运行。
