A device for achieving multi-
photon interference, said device comprising: at least two 
solid state 
photon emitters, each 
solid state 
photon emitter comprising nuclear and 
electron spin states coupled together, each 
solid state photon emitter being configured to produce 
photon emission comprising a 
photon emission peak, wherein the 
photon emission peaks from different 
solid state photon emitters have a first 
frequency difference between peak intensities, and wherein the 
electron spin states of each 
solid state photon emitter are resolvable; an excitation arrangement configured to individually address the at least two 
solid state photon emitters; a plurality of optical out 
coupling structures wherein each solid state photon emitter is provided with an associated optical out 
coupling structure; a tuning arrangement configured to reduce the first 
frequency difference between the peak intensities of the photon emission peaks from the at least two solid state photon emitters to a second 
frequency difference which is smaller than the first frequency difference; a photon interference arrangement configured to overlap photon emissions from the at least two solid state emitters after tuning; and a 
detector arrangement configured to detect photon emissions from the at least two solid state emitters after tuning and passing through the photon interference arrangement, wherein the 
detector arrangement is configured to resolve sufficiently small differences in 
photon detection times that tuned photon emissions from the at least two solid state emitters are 
quantum mechanically indistinguishable resulting in 
quantum interference between indistinguishable photon emissions from different solid state photon emitters.