Robust manipulation of electron spin coherence in an ensemble of singly charged quantum dots

Using the recently reported mode-locking effect [A. Greilich et al., Science 313, 341 (2006)], we demonstrate a highly robust control of electron spin coherence in an ensemble of (In,Ga)As quantum dots during the single spin coherence time. The spin precession in a transverse magnetic field can be fully controlled up to $25\mathrm{K}$ by the parameters of the exciting pulsed laser protocol such as the pulse train sequence, leading to adjustable quantum beat bursts in Faraday rotation. Flipping of the electron spin precession phase was demonstrated by inverting the polarization within a pulse doublet sequence.