Quantum Control Of Single Nitrogen Vacancy Color Centre In Diamond

Since the birth of quantum mechanics in last century, people gain deep insight into the natural world with the power of quantum mechanics. As the development of science and technology, human beings have reached the quantum level to control or manipulate the world, and the quantum information science emerge. The control of quantum systems will have profound influence to quantum information field. However, quantum systems are often very fragile and easy to decoherence because of the influence by the environment, it is not easy to control them. Today, different kinds of quantum systems are studied. The Nitrogen Vacancy color center(NV center) in diamond has attracted more and more attentions because of its advantages of easily to integrate, long coherence time at room temperature, the abilities of initialization and readout, and microwave control. It mainly focus on the quantum control of single NV center in this thesis.Firstly, I make a brief introduction of the basic properties of NV center in diamond and analyze the main reasons that cause the decoherence of the NV center electron spin. I also briefly discuss the applications of NV center in quantum metrology and quantum computing.Secondly, I will tell that we experimentally demonstrate on that by using a continuous-wave dynamical decoupling method on a NV center system, we might not only prolong the coherence time by about 20 times but also protect the quan-tum gates for the duration of the controlling time. This protocol shares the merits of retaining the superiority of prolonging the coherence time and at the same time easily combining with quantum logic tasks. This method can be useful in tasks where the duration of quantum controlling exceeds far beyond the dephasing time and quantum metrology.Thirdly, I will describe how we study the non-Markovian behavior of quantum dynamics of NV center by entangling the NV center electron spin and the proximal 13C nuclear spin. By using dynamical decoupling, we prolong the decoherence time of entanglement and reveal the quantum non-Markovianity concealed in the environment.Fourthly, in order to study and use the excited state property of NV center, we built the low temperature ODMR set-up. We realize the excited state level tuning by using Stark effect. By using the solid immersion lens and resonant fluorescence, we realize the single shot readout the single electron spin of NV center with the fidelity of 90%.At last, I make a conclusion of this thesis. I discuss the problems on the road to practical quantum computing and quantum network with NV center. and propose the possible solution of practical quantum network.