Electromagnetically induced transparency and light storage in an atomic Mott insulator

We experimentally demonstrate electromagnetically induced transparency and light storage with ultracold Rb-87 atoms in a Mott insulating state in a three-dimensional optical lattice. We have observed light storage times of similar or equal to 240 ms, to our knowledge the longest ever achieved in ultracold atomic samples. Using the differential light shift caused by a spatially inhomogeneous far detuned light field we imprint a ``phase gradient'' across the atomic sample, resulting in controlled angular redirection of the retrieved light pulse.