ABSTRACT
This chapter discusses advantage of the many-body Coulomb interactions to generate and manipulate nonradiative quantum coherences. It describes theoretically, the manifestation and behavior of electromagnetically induced transparency (EIT) processes in transient regimes. The chapter also discusses experimental demonstrations of EIT using excitons in gallium arsenide quantum-well structures. It shows that many-body Coulomb interactions between excitons can be exploited for the generation and manipulation of exciton spin coherence and biexciton coherence. The chapter provides the similarities and especially the essential differences in EIT processes between atomic and excitonic systems. It focuses on the changes in the absorption spectrum induced by EIT; these changes are also accompanied by corresponding changes in the refractive index. The absorption spectrum features a distinct EIT dip similar to that observed for cw excitations. The experimental setup for transient EIT studies was based on a standard transient pump-probe configuration, but with different pump and probe pulse durations.
