Device Produces Controllable Single Photons from Quantum Dots

For quantum computing applications, it will be necessary to control emissions from quantum emitters, or quantum dots (QDs), and to produce quantum entanglement of the emission from pairs of QDs. A new photon-emitting device developed at Trinity College Dublin enables controllable, directional emission of single photons from QDs and can produce entangled states of pairs of QDs. To create the device, the researchers focused a plasmonic waveguide within a few nm of a surface containing the QDs. When they excited the tip of the waveguide, it generated enough power over a sufficiently small region to strongly drive quantum emitters. This enabled ultrafast single-photon emission, and also created entangled states between two emitters when...