Efficient light storage in a crystal using an atomic frequency comb

Abstract

We demonstrate efficient and reversible mapping of a light field onto a\nthulium-doped crystal using an atomic frequency comb (AFC). Thanks to an\naccurate spectral preparation of the sample, we reach an efficiency of 9%. Our\ninterpretation of the data is based on an original spectral analysis of the\nAFC. By independently measuring the absorption spectrum, we show that the\nefficiency is both limited by the available optical thickness and the\npreparation procedure at large absorption depth for a given bandwidth. The\nexperiment is repeated with less than one photon per pulse and single photon\ncounting detectors. We clearly observe that the AFC protocol is compatible with\nthe noise level required for weak quantum field storage.\n