Ultrafast and time-resolved Raman spectroscopy of spin excitations in p-doped semiconductor heterostructures

We investigate the spin dynamics of holes and the dynamics of elementary excitations of holes in undoped and p-doped GaAs-AlGaAs quantum-well systems. In one part of the project, a very long hole-spin coherence, which we have observed recently at low temperatures, shall be studied concerning its dependence on band mixing, symmetry of the confining potential and presence of remote dopants. Employing time-resolved Faraday/Kerr experiments, time-resolved photoluminescence and resonant spin amplification, we will explore hole spin initialization mechanisms and the limits of hole spin coherence at low temperatures and small magnetic fields. In a second project part, we investigate spin-density excitations of holes via Raman spectroscopy. Here, the anisotropy of these charge-neutral spin excitations with respect to different crystal directions and the dynamics of the excitations shall be explored.