Subspace Control of Nitrogen Vacancy centers at Zero Field

Abstract

Nitrogen-Vacancy centers negatively charged (NV-) are spin-1 objects in diamond. In the absence of a magnetic field, two of its levels are degenerate, which is why a field is often used to lift the degeneracy and allow easy access to each level. Following the work of Alegre, Mrozek and others, it was established that circularly polarized microwaves could address the difference in angular momentum between each level, making the introduction of the magnetic field unnecessary. These methods were assuming that the position of the microwave sources and the NV- was ideal. There was then work to be done to enable circularly polarized microwaves to work with an NV- at any position. To handle this freedom in the NV- position, characterization methods need to be developed to measure it and take it into account. This can be done with a custom-built confocal microscope, taking into account the orientation of a single NV-.