A transistor-like amplifier for single photons
Data transmission over long distances usually utilizes optical techniques via glass fibres – this ensures high speed transmission combined with low power dissipation of the signal. For quite some years possibilities have been explored how to go one step further and perform all-optical data processing, with optical transistors and optical logic gates. In particular in the case of quantum information this option would be highly recommendable as the information is often stored in faint light pulses which – at the ultimate limit – contain a single photon only. A team around Professor Gerhard Rempe, Leader of the Quantum Dynamics Division and Director at the Max Planck Institute of Quantum Optics, has now made a kind of optical transistor using a cloud of ultracold rubidium atoms. With this new device they observed a twentyfold amplification of signal variations at the one-photon level.