Optimizing inhomogeneous spin ensembles for quantum memory
  We propose a general method to maximize the fidelity of writing, storage and reading of quantum information (QI) in a spectrally inhomogeneous spin ensemble used as quantum memory. The method is based on preselecting the optimal spectral portion of the ensemble by a judiciously designed pulse. It allows drastic improvement of quantum memory realized by spin ensembles that store QI from a resonator or an optical beam. 
Guy Bensky and David Petrosyan and Johannes Majer and J\"org   Schmiedmayer and Gershon Kurizki
quant-ph