  Electron spin dephasing in a singly charged semiconductor quantum dot can
partially be suppressed by periodic laser pulsing. We propose a semi-classical
approach describing the decoherence of the electron spin polarization governed
by the hyperfine interaction with the nuclear spins as well as the
probabilistic nature of the photon absorption. We use the steady-state Floquet
condition to analytically derive two subclasses of resonance conditions
excellently predicting the peak locations in the part of the Overhauser field
distribution which is projected in the direction of the external magnetic
field. As a consequence of the periodic pulsing, a non-equilibrium distribution
develops as a function of time. The numerical simulation of the coupled
dynamics reveals the influence of the hyperfine coupling constant distribution
onto the evolution of the electron spin polarisation before the next laser
pulse. Experimental indications are provided for both subclasses of resonance
conditions.
