Coherent spin oscillations in bulk GaAs at room temperature

Time-resolved Kerr rotation in Voigt geometry is used to study the coherent evolution of spin states in moderately doped n-GaAs crystals with picosecond excitation. Due to the small spectral width of the exciting laser pulses, selective excitation of different electronic states is feasible, which allows one to extract both the dependence of the g factor and the spin dephasing time on energy. The authors are able to observe coherent spin oscillations in bulk n-GaAs at room temperature and deduce a g factor of g=−0.316±0.004 at 300K and a magnetic field dependent room temperature spin dephasing time of, e.g., T2*=110ps at B=1.2T.