Electromagnetically induced transparency and retrieval of light pulses in a Pr3+:Y2SiO5 crystal

Recent research on coherent interactions between light and matter already led to a large variety of applications. In particular electromagnetically induced transparency (EIT) and the closely related concepts of slow light and light storage play an important role in quantum information processing and optical data storage. A very promising approach is the implementation of these techniques in solids, e.g. in particular rare earth doped solids. These media offer the advantages of solids, i.e. high density and scalability, while still exhibiting sharp optical transitions - like free atoms in the gas phase. We apply EIT and related techniques in a Pr3+:Y2SiO5 crystal, cooled to cryogenic temperatures. The dopant ions are prepared by optical pumping and spectral holeburning. This permits the generation of spectrally isolated Λ-type or V-type systems within the inhomogeneous bandwidth of the 3H4 <-> 1D2 transition of the Pr3+ ions. We observe and compare cancellation of absorption due to EIT in the Λ-type coupling scheme as well as in the V-type coupling scheme. By EIT, we also excite persistent nuclear spin coherences between the hyperfine levels of the ground state (Λ-System) or the excited state (V-system). These coherences are probed by time delayed retrieval of light pulses. Hereby we determine the dephasing times of the nuclear spin coherences of the Pr3+ ions, either in the ground state or in the optically excited state