Electronic circuits are based on electrons, but one of the most
promising technologies for future quantum circuits are photonic circuits, i.e.
circuits based on light (photons) instead of electrons. First, it is necessary
to be able to create a stream of single photons and control their direction.
Researchers around the world have made all sorts of attempts to achieve this
control, but now scientists at the Niels Bohr Institute have succeeded in
creating a steady stream of photons emitted one at a time and in a particular
direction. The breakthrough has been published in the scientific journal
Physical Review Letters.