The ability to generate single photons on demand represents an enabling technology for future computing and secure communications.  In quantum computing, single photons can be used to transfer information, or even be manipulated to perform logic.  In communications, quantum key distribution uses the fundamental nature of quantum particles to ensure that eavesdroppers and hence security risks can always be detected.  However, all of these exciting applications depend on the ability to generate single photons on demand, without a risk of sometimes generating multiple photons.

Generating a pure single photon stream has been particularly challenging for photons of blue wavelengths, which might be used for satellite to satellite quantum communications.  Here, we demonstrate that by creating an indium gallium nitride single quantum emitter within a pillar structure, sandwiched between multilayer mirrors made from porous gallium nitride, we can generate single photons with record high purity, giving these structures relevance to applications which were previously thought to be inaccessible using these materials.  

Figure caption: Schematic of record breaking InGaN single photon source