arXiv:0912.2525 · Physical Review Letters
Storage and Recall of Weak Coherent Optical Pulses with an Efficiency of 25%
Mahmood Sabooni, F. Beaudoin, Andreas Walther, Nan Lin, A. Amari, Ming Huang, Stefan Kröll
Abstract
We demonstrate experimentally an efficient coherent rephasing scheme for the storage and recall of weak coherent light pulses in an inhomogeneously broadened optical transition in a Pr(3+):YSO crystal at 2.1 K. Precise optical pumping using a frequency stable (≈1 kHz linewidth) laser is employed to create a highly controllable atomic frequency comb structure. We report single photon level storage and retrieval efficiencies of 25%, based on coherent photon-echo-type reemission in the forward direction. The high efficiency is mainly a product of our highly controllable and precise ensemble-shaping technique. The coherence property of the quantum memory is proved through interference between a super-Gaussian pulse and the emitted echo.