Abstract: Systems and methods are disclosed for making a quantum network node. A plurality of scoring function F values are calculated for an array of at least two photonic crystal cavity unit cells, each having a lattice constant a and a hole having a length Hx and a width Hy. A value of a, a value of Hx, and a value of Hy are selected for which a scoring function value is at a maximum. A waveguide region and the array of at least two photonic crystal cavity unit cells based on the selected values are formed on a substrate. At least one ion between a first photonic crystal cavity unit cell and a second photonic crystal cavity unit cell are implanted and annealed into a quantum defect. A coplanar microwave waveguide is formed on the substrate in proximity to the array of at least two photonic crystal cavity unit cells.

Abstract: Systems and methods are disclosed for preparing and evolving atomic defects in diamond. Silicon vacancy spins may be cooled to temperatures equal to or below 500 mK to reduce the influence of phonons. The cooling, manipulation, and observation systems may be designed to minimize added heat into the system. A CPMG sequence may be applied to extend coherence times. Coherence times may be extended, for example, to 13 ms.

Abstract: Systems and methods are disclosed for preparing and evolving atomic defects in diamond. Silicon vacancy spins may be cooled to temperatures equal to or below 500 mK to reduce the influence of phonons. The cooling, manipulation, and observation systems may be designed to minimize added heat into the system. A CPMG sequence may be applied to extend coherence times. Coherence times may be extended, for example, to 13 ms.