Coherent control of bound entangled electrons in a CdMnTe quantum well

Abstract

Ultrafast laser pulses were used to control the spin state of a pair of entangled, donor‐bound electrons in a CdMnTe quantum well. The entanglement, mediated by an optically‐excited exciton, was characterized by pumpprobe spectroscopy. The data exhibits two dominant oscillations, one at the frequency of the spin‐flip of a donor electron and the second one at twice this frequency. Their amplitudes depend linearly on the pump power. The quantum state of the two‐electron spin system can be controlled by appropriate spatial and temporal shaping of the pump pulses. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)