Decoherence Effects in a Light Storage Experiment

Eden V. Figueroa, Juergen Appel, Frank Vewinger +1 more

David C K Roberts, Thomas Gasenzer, Keith R. Burnett

We investigate the limitations arising from atomic collisions on the storage and delay times of probe pulses in electromagnetically induced transparency experiments. We find that the atomic collisions can be described by an effective decay rate that limits storage and delay times. We calculate the momentum and temperature dependence of the decay rate and find that it is necessary to excite atoms at a particular momentum depending on temperature and spacing of the energy levels involved in order to minimize the decoherence effects of atomic collisions.

J. M. Raimond

Schlosshauer-Selbach, Andreas M

Rami Pugatch, M. Shuker, Ofer Firstenberg +2 more

We report an experiment in which an optical vortex is stored in a vapor of Rb atoms. Because of its 2pi phase twist, this mode, also known as the Laguerre-Gauss mode, is topologically stable and cannot unwind even under conditions of strong diffusion. For comparison, we stored a Gaussian beam with a dark center and a uniform phase. Contrary to the optical vortex, which stays stable for over 100 micros, the dark center in the retrieved flat-phased image was filled with light after a storage time as short as 10 micros. The experiment proves that higher electromagnetic modes can be converted into atomic coherences and that modes with phase singularities are robust to decoherence effects such as diffusion. This opens the possibility to more elaborate schemes for classical and quantum information storage in atomic vapors.

Hong Mei Guo

Recently,direct light storage based on quantum coherent effects has been proved to be effective throngh experiment.Compared with lots of light storage techniques,quantum coherent storage has a lot in common with widely used traditional magnetic storage technique both in theories and applications.Here this paper compares the magnetic storage and the new storage technique based on the theory of dark state polaritons(DSP) realized using electromagnetic induced transparency (EIT) method.Then it's pointed out that the DSP storage time cannot be extended to classical level in free atomic gases with the lack of the correlations between the atoms.Finally,how the problem could be solved is discussed.