Stuttgart 2012 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 61: Quanteneffekte: Lichtstreuung

Q 61.2: Vortrag

Freitag, 16. März 2012, 10:45–11:00, V7.01

Enhanced optical data storage up to 1 second by EIT in a doped solid — •Georg Heinze, Christian Hubrich, Simon Mieth, and Thomas Halfmann — Institut für Angewandte Physik, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt

Efficient and long-time storage of coherent optical data is one key ingredient towards future quantum information processing. Several approaches to implement quantum memories have been proposed and investigated. Among these, the storage of light in atomic coherences, driven by electromagnetically induced transparency (EIT) is a prominent example. But, similar to other coherent interactions also EIT suffers from decoherence. This is a major obstacle for quantum memories and limits both efficiency as well as storage time considerably.

The talk reports on the storage of light pulses and images by EIT in a rare-earth-ion doped solid (Pr³⁺:Y₂SiO₅) – approaching storage times in the regime of 1 second. The long storage times are possible by a combination of powerful approaches: First, we apply well-defined static magnetic fields to minimize the perturbation of atomic coherences (which serve to store the optical information) from external spin fluctuations. Second, we increase coherence times by specific RF pulse sequences, which allow for efficient dynamic decoupling of the atomic coherences from the environment. Third, we apply feedback-controlled pulse shaping and evolutionary algorithms to automatically determine optimal preparation pulse sequences in the complex level system. The unique combination of these techniques enhances both the efficiency as well as the storage times by orders of magnitude.