Probing of Spin Wave Resonances in (Ga,Mn)As by Time-Resolved Magneto-Optical Technique

We report on all-optical detection of magnetization dynamics in the ferromagnetic semiconductor (Ga,Mn)As in the presence of spin-wave resonances (SWRs) using a time-resolved magneto-optical (TRMO) technique. In our previous experiments, we demonstrated the possibility to reconstruct the magnetization dynamics directly from the TRMO signals. In this paper, we present a detailed time-domain analysis of the TRMO traces obtained using this method to determine the exact influence of the higher SWR modes on the laser-induced magnetization dynamics. We focus on the effect of the SWR on the evolution of the spatially averaged magnetization.