A proof-of-concept device that could pave the way for on-chip optical quantum networks has been created by a group of researchers from the US.
Presenting the device today, 8 February, in the Institute of Physics and German Physical Society's New Journal of Physics, it has been described as the "building block of future quantum networks."
In an optical quantum network, information is carried between points by photons the basic unit of light. There is a huge potential for this type of network in the field of quantum computing and could enable computers that are millions of times faster at solving certain problems than what we are used to today.
This new device, which combines a single nitrogen-vacancy centre in diamond with an optical resonator and an optical waveguide, could potentially become the memory or the processing element of such a network.
A nitrogen-vacancy centre is a defect in the lattice structure of diamond where one of the carbon atoms is replaced by a nitrogen atom and the nearest neighbour carbon atom is missing. The nitrogen-vacancy centre has the property of photoluminescence, whereby a substance absorbs photons from a source and then subsequently emits photons.
The emitted photons are special in that they are correlated, or entangled, with the nitrogen-vacancy centre that they came from, which as the researchers state is crucial for future experiments that will look to examine this correlation. You cannot get these correlated photons from a normal light source.
In this device, the photons are produced from a nitrogen-vacancy centre within a diamond microring resonator. The nitrogen-vacancy centre is located inside the diamond resonator as it is more likely to emit photons than when it is located in the waveguide or just in plain diamond. Moreover, the photons emitted in the resonator are easier to couple into an on-chip waveguide.
The cotton bud-shaped waveguide sen
|Contact: Michael Bishop|
Institute of Physics