Look, the herald photon source shines!
A lot of quantum applications require single photons, which have to be generated in so called single photon sources. It is essential to control the timing of the single photon emission or at least to know whether a single photon is emitted from such a source or not. To get this information one has to detect the output of the source. The issue is that detection of photons means annihilation. A solution to this problem is to generate single photon pairs and detect only one of them to herald the other photon.
The implementation of this concept requires different components for the creation of a single photon pair and the subsequent separation. For a commercial use of such a source, it is important to combine all the components in one small robust device. This is exactly one part of the UNIQORN project.
Heralded single-photon source and device characterisation in the lab.