Spin coherence of holes in GaAs/AlGaAs quantum wells

Pump-probe time-resolved Kerr rotation technique has been used for experimental investigation of hole spin coherence in 15-nm wide GaAs/AlGaAs quantum well structure in regime of diluted two-dimensional hole gas. Due to the spectral width of 1.5 ps laser pulses which correspond to similar to 1 meV, selective excitation of trion and exciton states has been performed. In the case of resonant excitation of exciton only the electron spin beats have been observed in the presence of magnetic field. In the case of resonant excitation of the positively charged exciton two component decay of time-resolved Kerr rotation (TRKR) signal appeared. From the period of the quantum beat oscillation related to long decay component (up to 650 ps) of TRKR signal we obtained in-plain hole g-factor of similar to 0.048 +/- 0.005.