Laser-induced magnetization dynamics

During the past few years, a wealth of new data on laser-induced ultra-fast magnetization dynamics in ferromagnetic metals has become available. Many of the recent approaches employed time-resolved magneto-optical strategies. In principle, these experiments have provided detailed insight into the fundamental physics involved, but it has become clear that the magneto-optical view is rather indirect. Utmost care is needed in analyzing transient magneto-optical studies. Among phenomena triggered by a short laser pulse are ultrafast demagnetization, dichroic state filling, piezo-optical effects and laser-induced precession. This chapter discusses the interplay between optics and magnetism in the ultrafast regime; provides quantitative analysis of experimental schemes; and includes a historical review of experiments and theory on laser-induced magnetic phenomena, predominantly concentrating on ferromagnetic transition metals. Particular emphasis is on the subtle interpretation of experiments and recent breakthroughs therein.