Electron spin coherence in singly charged (In,Ga)As/GaAs quantum dots

Optical generation of electron spin coherence has been studied in n -modulation doped (In,Ga)As/GaAs quantum dots which contain on average a single electron per dot. For studying the spin coherence, the magnetic field was applied in the Voigt-geometry, and the precession of the electron spin about the field was monitored. The coherence is generated by resonant excitation of the quantum dots by circularly-polarized laser pulses, creating a coherent superposition of an electron and a trion state. The efficiency of the generation can be controlled by the pulse intensity, showing the pronounced Rabi oscillations. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)