Gabriel Hétet

We report observations of the Electron Spin Resonance (ESR) of Nitrogen Vacancy (NV) centers in diamonds that are levitating in an ion trap. Using a needle Paul trap operating under ambient conditions, we demonstrate efficient microwave driving of the electronic spin and show that the spin properties of deposited diamond particles measured by the ESR are retained in the Paul trap. We also exploit the ESR signal to monitor the rotation of levitating monocrystals, a first step towards spin-controlled mechanical systems in scattering-free traps.

Trapped ion crystals have proved to be one of the most viable physical implementations of quantum registers and a promising candidate for a scalable realization of quantum networks. The latter will require the development of an efficient interface between trapped ions and photons. We describe two research directions that are currently investigated to realize such photonic quantum interfaces in free space using high numerical aperture optics. The first approach investigates how strong focusing of light onto a single ion can increase the interaction strength to achieve efficient interaction between a photon and the ion. The second approach uses a probabilistic measurement on scattered photons to generate entanglement between two ions that could be used to distribute information in a quantum network. For both approaches a higher numerical aperture would increase the efficiency of the interface.