Quantum information with NV - centers in diamond

Philip Hemmer

Charles Santori, Kai‐Mei C. Fu, Paul E. Barclay +1 more

We describe research on new optical structures in diamond for quantum information and sensing applications based on the nitrogen-vacancy (NV) center. Results include etching experiments that reveal the vertical distribution of NV centers produced by ion implantation and annealing, and gallium phosphide waveguides fabricated on diamond with evanescent coupling to NV centers close to the diamond surface.

Kouichi Semba

Michael Gould, Srivatsa Chakravarthi, Ian Christen +6 more

We present chip-scale transmission measurements for three key components of a gallium-phosphide (GaP)-on-diamond integrated photonics platform: waveguide-coupled disk resonators, directional couplers, and grating couplers. We also present proof-of-principle measurements demonstrating nitrogen-vacancy (NV) center-emission coupled into selected devices. The demonstrated device performance, uniformity, and yield place the platform in a strong position to realize measurement-based quantum information protocols utilizing the NV center in diamond.

Norikazu Mizuochi

Margarita Lesik

The Nitrogen-Vacancy (NV) color center is a defect of diamond which behaves as an artificial atom hosted in a solid-state matrix. Due to its electron spin properties which can be read-out and manipulated as an elementary quantum system, the NV center has found a wide panel of applications as a qubit for quantum information and as a magnetic field sensor. However these applications require to control the properties of the NV centers and their localization. This doctoral thesis investigates methods allowing us to tailor the properties of NV centers by combining techniques for the implantation of nitrogen atoms and the plasma-assisted (CVD) synthesis of diamond.The manuscript is divided into six chapters. The first chapter summarizes the properties of the NV center which will set our objectives for the NV engineering. The second chapter will describe how arrays of NV centers can be created using Focused Ion Beam implantation. The results open a wide range of applications for the targeted creation of NV centers in diamond structures such as photonic crystals and tips. However the low kinetic energy which is required for achieving implantation within a spot of 10-nm diameter leads to shallow defects which properties are strongly affected by the sample surface. The third chapter investigates how the overgrowth of a diamond layer over implanted NV centers can remove the detrimental influence of the surface. The fourth and fifth chapters describe effective methods for NV center fabrication through the control of the CVD growth conditions of the hosting crystal. Thin layers with high NV doping can be grown and almost perfect control of the orientation of the NV axis can be achieved. With the goal to optimize the spin coherence properties, the sixth chapter investigates how the electron spin of the NV center can be protected from decoherence effects induced by magnetic noise due to the unpolarized spins in the diamond lattice.