Electromagnetic induced tranparency in bulk and microcavity semiconductors

We discuss our recent results on electromagnetically induced transparency (EIT) effects based on intrinsic free exciton and biexciton states in semiconductors. The Lambda configuration obtained from the IS and 2P yellow exciton levels of Cu2O leads to a well-developed EIT regime, akin to the atomic case. The coherent driving of the exciton-biexciton transition in CuCl induces a tunable transparency window within the polaritonic stop-band, due to the presence of a third polariton branch in the dressed system. In a microcavity configuration, this gives rise to three reflectivity dips in the strong coupling regime