Experiments towards a periodically pumped single-photon source are presented. The lateral piezoelectric field of a surface acoustic wave dissociates laser-generated two-dimensional excitons into electrons and holes. These carriers are separated by the wave potential and are transported over macroscopic length scales without recombining. When reaching a stress-induced quantum dot in the quantum well they periodically populate the zero-dimensional states and recombine, emitting single photons periodically in time according to the surface acoustic-wave frequency. We have successfully reduced the number of pumped quantum dots down to 100 and have detected a strong blinking photoluminescence signal. By further reducing the number of quantum dots down to 1 a periodically pumped single photon source could be realized.
Bödefeld, C., Ebbecke, J., Toivonen, J., Sopanen, M., Lipsanen, H., & Wixforth, A. (2006). Experimental investigation towards a periodically pumped single-photon source. Physical Review B, 74(3), 1-5. . https://doi.org/10.1103/PhysRevB.74.035407