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Single Photons from Isotopically-pure Rubidium Atoms in a Long fibre


Single photon sources are essential for applications of quantum optics. For optical quantum computing the process is probabilistic and so the larger the number of photons the less time required for success. Therefore, there has been a push to increase the brightness of single photons sources. This goal of this action is to develop a source of heralded single photons with a very high spectral brightness, based on four-wave mixing in an alkali-vapour contained in a hollow core photonic
crystal fibre. This will exploit the higher efficiency expected from using a hollow core fibre to boost the brightness of the single-photon source. Also, by using optical fibre technology, this photon source should be very simple to integrate into other systems. Once the photon pairs are generated, the major challenge of this system will be to split them from themselves, as well as removing the vast number of remaining pump photons. Since all three wavelengths of the light emerging from the
fibre are very close to each other, and the beams are spatially overlapped, many common techniques (such as using interference filters and/or spatial filtering) will not work. However, we have identified a scheme using an atomic Faraday filter which will allow a beam splitter to be formed for the photon pairs, whilst simultaneously removing the pump photons.

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Keplerstrasse 7
70174 Stuttgart
Activity type
Higher or Secondary Education Establishments
EU contribution
€ 132 884