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Q: Quantenoptik und Photonik
Q 7: Quantenkommunikation
Q 7.4: Vortrag
Montag, 22. März 2004, 17:15–17:30, HS 101
Multiplexed quantum cryptography with cascaded photons from a single quantum dot — •Thomas Aichele1, Valéry Zwiller2, Gaël Reinaudi1, and Oliver Benson1 — 1Humboldt-Universität zu Berlin, Nano-Optik — 2Ecole Polytechnique Fédérale de Lausanne, Switzerland
Efficient generation of single photons is an important task for modern quantum technology such as quantum computation and quantum cryptography. In quantum cryptography with single photon sources the transition lifetime limits the maximum achievable transmission rate of quantum bits.
Here we present and demonstrate a method to further enhance the effective transmission rate by using multiplexing similar as in classical communication channels. This method relies on cascaded multi-photon emission that is observed in single InP quantum dots (QDs). Cross correlations between different photoluminescence spectral lines prove the excistence of this cascade and also reveal their dynamics. Auto-correlation measurements on both the individual spectral lines as on the multiplexed signal show single photon statistics. As a proof of principle we implemented a BB84 quantum cryptography setup using this multiplexing technique.