We will demonstrate the operation of a fiber-coupled spin qubit with ultra-high fidelity optical readout. We employ submicron tapered-fiber waveguides to evanescently couple to the modes of a diamond nanowire containing a single nitrogen-vacancy (NV) center. This method of coupling will enable record high photon channeling efficiency into a single mode of an optical fiber, thus improving readout fidelity of the NV spin state.

For use as a qubit, the NV center spin state will be controlled using resonant microwave excitations at approximately 2.87 GHz. Our resulting system will be useful as a building block for a large quantum network.

In my quantum mechanics classes I was always fascinated by the dynamics of two level systems and the practical applications enabled thereof, such as in lasers and nuclear magnetic resonance imaging. When I realized that quantum engineering of a two-state system could be implemented with solid state NVs, I was drawn towards this research.