Nature Nanotechnology – A diamond nanowire single-photon source Nanowire devices are pumped an order of magnitude more efficiently than bulk devices and allow for an order of magnitude higher
The development of a robust light source that emits one photon at a time will allow new technologies such as secure communication through quantum cryptography. Devices based on fluorescent dye molecules, quantum dots and carbon nanotubes have been demonstrated, but none has combined a high singlephoton flux with stable, room-temperature operation. Luminescent centres in diamond have recently emerged as a stable alternative, and, in the case of nitrogen-vacancy centres, offer spin quantum bits with optical readout. However, these luminescent centres in bulk diamond crystals have the disadvantage of low photon out-coupling. Here, we demonstrate a single-photon source composed of a nitrogenvacancy centre in a diamond nanowire, which produces ten times greater flux than bulk diamond devices, while using ten times less power. This result enables a new class of devices for photonic and quantum information processing based on nanostructured diamond, and could have a broader impact in nanoelectromechanical systems, sensing and scanning probe microscopy.
For the first time, we have used a top-down nanofabrication technique to enhance the optical properties of an individual colour centre in single-crystal diamond. The fabrication technique retains the crucial properties of an NV centre, and is compatible with the requirements needed for the realization of scalable quantum systems based on diamond. Further fundamental studies of the properties of an NV centre in diamond nanostructures will facilitate their integration into more complex photonic quantum information devices, in which more advanced functions such as increasing the photon production rate by means of the Purcell effect will allow devices operating at even higher count levels and lower powers. Finally, by implanting colour centres in nanowires fabricated in
ultrapure diamond, simultaneous optimization of both spin and optical properties will be possible in a single device.