Diamond imperfections enable quantum computers
Colour centres in a diamond are an ideal test bed for applications of quantum information processing and for spin-spin interactions. While there are hundreds of known colour centres in a diamond, only one (nitrogen-vacancy) has received diligent attention. Within the PLACQED (Plasmonic cavity quantum electrodynamics with diamond-based quantum systems) project, scientists focused on alternative colour centres such as chromium and silicon vacancies. The team reported one of the narrowest typical linewidths for diamond-based emitters to date. Results also showed that the optical transition frequency can be tuned via voltage, rendering these systems attractive for spectral control of photonic states. Scientists then proceeded with showing that resonant optical excitation leads to spin-tagged fluorescence for silicon-vacancy centres with high spin purity. In parallel, they demonstrated spectral tunability of a plasmonic nanoantenna mode by modifying the antenna environment in a controlled fashion. This was achieved by manipulating the positioning of a dielectric nanostructure. These newly developed coupled emitter-antenna systems can serve as a testbed for plasmon-based electro-optic circuitry. Incorporating colour centres in plasmonic cavities enhances our understanding of the interaction between light confined in a reflective cavity and atoms. Cavity quantum electrodynamics could be used to construct quantum computers.
