Electromagnetically Induced Transparency via Spin Coherences in Semiconductors

I will review recent progresses on the realization and application of electromagnetically induced transparency in semiconductors. The emphasis will be on the use of electron spin coherence in quantum well structures. Electromagnetically induced transparency (EIT) exploits destructive quantum interference induced by a nonradiative quantum coherence to make an otherwise opaque medium transparent. EIT and EIT-related processes provide a powerful and effective mechanism for controlling and manipulating light. While most EIT studies have thus far been carried out in atomic or atomic-like systems, the basic concept of EIT can also be applied to optical excitations in semiconductors. In this talk, I will discuss recent progresses on EIT studies in semiconductors. There are two major obstacles for realizing EIT and, more generally, for coherent manipulation of quantum coherences in semiconductors. First of all, with the exception of electron spin coherence, quantum coherences in semiconductors are typically short lived and are extremely fragile against dynamic processes such as carrier-carrier and carrier-phonon scattering. Secondly, coherent nonlinear optical processes in semiconductors are profoundly modified by manybody Coulomb interactions between carriers. I will discuss various EIT schemes that have been used to take advantage of the robust electron spin coherence in semiconductors and to harness effects of inherent manybody Coulomb interactions.