All-optical implementation of a dynamic-decoupling protocol for hole   spins in (In,Ga)As quantum dots
  We demonstrate the potential of a periodic laser-pulse protocol for dynamic decoupling of hole spins in (In,Ga)As quantum dots from surrounding baths. When doubling the repetition rate of inversionlaser pulses between two reference pulses for orienting the spins, we find that the spin coherence time is increased by a factor of two. 
S. Varwig, E. Evers, A. Greilich, D. R. Yakovlev, D. Reuter, A. D.   Wieck, and M. Bayer
cond-mat.mes-hall