Resonant Faraday rotation: internal clock for ultra-fast processes

The aim of this paper is to show how the idea of resonant Faraday rotation, born in the group of Claude Benoit a la Guillaume in the seventies, found its application more than ten years later to study fast kinetics of excitonic states in semimagnetic semiconductors in the same laboratory and elsewhere. Characteristic times in the picosecond- and subpicosecond range can be determined by measurements of linear polarization of the Raman lines in longitudinal magnetic field. After a brief explanation of the mechanism of resonant Faraday rotation, its application will be discussed to Raman cascades involving intra-ion excitations in CdFeSe bulk crystals, classical Raman processes in several semimagnetic compounds, and perspectives of its use to analyze Raman cascades involving spin resonance transitions in CdMnTe quantum wells. (orig.)