  An efficient quantum storage is highly desired for quantum information
processing. As indicated by certain applications, a universal quantum storage
is required to have a storage efficiency above 50% to beat the no-cloning
limit. Although significant progress has been achieved in improving various
quantum storage, the best storage efficiency of single photons is still below
this criteria. By integrating a highly controllable single photon source with
an optimized quantum storage, here we demonstrate an optical storage of single
photons with storage efficiency of 65% in a cold atomic ensemble based on
electromagnetically induced transparency. Meanwhile, the nonclassical
characteristics of our storage are verified through the well-maintained
nonclassical and single photon nature of the retrieved single photons.
