Project PEGASOS was a feasibility study for the use of our patented single-photon source array technology as a next-generation light source for free-space and satellite-based quantum key distribution targeting faster and more power-efficient transmission of keys. Our method was based on controlled creation of single-photon sources in two-dimensional materials, including hexagonal Boron Nitride on patterned substrates. These patterns included nano-pyramids and nano-pillars, where the small deformation causes highly localised, deterministic activation of single photon emission. We have tested the concept on two novel platforms, first on hexagonal boron nitride multilayers and second on heterobilayer transition metal dichalcogenides. The technique worked for both material systems but with varying degree of success and we are in the process of identifying approaches to improve the yield. Next steps include taking this approach forward to build functional devices and integrate local spins to the single photon emitters, where we have had significant progress on this with hexagonal boron nitride. We are also in the process of filing new patents to develop a commercially viable product based on the arrays with better light extraction.
