| The NV center is a defect complex in the diamond,comprised of a substitutional nitrogen atom with an adjacent carbon vacancy.After getting an extra electron,the NV center become a NV-center.TheNV-center has attracted intensive investigation in last decade owing to its unique optical and spin properties at room temperature,which is promising for single photon source generation,quantum information and quantum metrology.Additionally,the biocompatibility of the diamond and the stability of the fuorescence of the NV center make it promissing to be used for biological fluorescent labelling and physical field detceting in living organism.NV centers can be found in natural diaond and nitrogen-doped HTHP and CVD grown diamond.However,the NV centers in these diamonds are randomly distributed,which will limit its aforementioned applications.In orde to overcome this problem,we adopted ions implantation which can introduce nitrogen atoms and geretate vacancies in diamond at desired position.And a subsequential annealing will generate desired NV centers for applicaitons.The major works of this thesis involves:building a optically detected magnetic resonance system for characterization and quantum manipulation of NV centers,determining the experimental procedures of some basic quantum manipulations,generating nanoscale arrays of NV centers with long coherence time in diamond by nitrogen ions implantation and high temperature annealing,generating NV center ensemble with high density by nitrogen ions implantation and high temperature annealingand applying the array of NV centers in detection of temperature distribution.This thesis is composed of five chapters:1.The first part of this thesis is the introduction.we first gave a briefly introduc-tion to quantum information:the concept and its significance.Then,we introduce the fundamental properities of diamond and NV centers.After that,we introduce the appli-caitons of NV center in many fields,such as single photon source,biological fluorescent label and quantum imformation.Finally,the major works of this thesis are outlined2.In the second chapter,we decribed our optically detected magnetic resonance(ODMR)system and some fundamental quantum manipulation techniques suitable for NV centers.Firstly,the building up of the laser confocal fluorescence microscope was described.We particularly analyzed the factors that affect the stability and singal to noise ratio of the microscope system,and then adopted a few measures to get better per-formances.Then,the ODMR system was set up,which was composed of the confocal microscope,mangetic filed and microwave systems.Based on the experimental system,we demonstrated the timing sychronization schems used in our pulse experiments.Fi-nally,we introduced the principles and experimental realizations of the continuous wave electron paramagnetic resonance,Rabi oscillation,free progress spin dynamics,Hahn echo and dynamic decoupling.3.In the third chapter,we summarized and analyzed the formation mechanism of NV centers and the major methods for generation of NV centers.Firstly,we introduced the fundamental properities of substitutional nitrogen atom and carbon vacancy.Then,we summarized and analyzed the formation mechanism of NV centers.Finally,we summarized the methods for generation of NV centers,and analyzed the advantages and disadvantages of these methods.Particularly,we demonstrated the obstacles we will encounter in the low-energy nitrogen ions implantation such as spatial precision of the center localization,yield of NV-center per implanted nitrogen atom,coherence time of the electronic spin and the charge state,and the methods for solving these obstacles.4.In the fourth chapter,we presented the experimential results on the efffcient gen-eration of nanosacle arrays of NV centers with long coherence time in diamond.The arrays were fabricated by nitrogen molecular ions(N2+)implantation into high purity CVD diamond(nitrogen concentration lower than 5 ppb)at a dose of 2.25×1011 cm-2 and an energy of 60 keV.About 47nm lateral spatial accuracy for NV center positioning was achieved.The high NV center generation efficiency and long coherence time were achieved by high temperature annealing of the implanted diamond.The yield of nega-tively charged NV centers was 18%with respect to the total implanted nitrogen ions and the proportion of the implanted sites containing single NV center reached 40%.The spin coherence time of the formed NV center was comparable with that of the native NV cen-ter,which confirmed the fact that high annealing has reduced the structure defects and paramagnetic defects generated during the process of nitrogen ions implantation.Using the dynamic decoupling,the coherence time of the NV centers generated in this work was extended to 1.4 millisecond,which enables an ac magnetic field detection with a sensitivity of 80 nT·Hz-1/2.5.In the fifth chapter,we demonstrated the experimental results on the creation of high density ensemble sof NV centers with nitrogen ions implantation.Nitrogen ions with four different doses and an energy of 50 keV were implanted on a diamond wafer covered with silicon masks,which were then treated with high temperature annealing and oxidizing.The measured fluorescence of the four areas of the sample indicated that increasing the dose did not significantly change the density of the NV centers when the dose was above 1014 cm-2.Then,we investigate the ratio of NV-/(NV-+NV0)in the four areas with photofluorescence spectroscopy.We found that the ratio increased with the nitrogen ions dose.Finally,we got the dephasing time of electron spin of NV centers in the four areas by ODMR measurement.The result indicated that the dephasing time has no significant change within the range of doses in our implantions.By combining the densities and dephasing time of NV centers in the four areas,we caculated the sensitivities of the centers used for optical metrology which indicated that the idea dose of nitrogen is about 3×1019 cm-3 in generation of high density ensembles of NV center for optical metrology. |
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