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All-optical depletion of dark excitons from a semiconductor quantum dot

Schmidgall, Emma R.; Schwartz, Ido; Cogan, Dan; Gantz, Liron; Heindel, Tobias; Reitzenstein, Stephan; Gershoni, David

AG Optoelektronik und Quantenbauelemente

Semiconductor quantum dots are considered to be the leading venue for fabricating on-demand sources of single photons. However, the generation of long-lived dark excitons imposes significant limits on the efficiency of these sources. We demonstrate a technique that optically pumps the dark exciton population and converts it to a bright exciton population, using intermediate excited biexciton states. We show experimentally that our method considerably reduces the dark exciton population while doubling the triggered bright exciton emission, approaching thereby near-unit fidelity of quantum dot depletion.
  • This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 106, 193101 (2015) and may be found at https://doi.org/10.1063/1.4921000.