Preparation And Related Research Of High Concentration NV Centers In Diamond

Nitrogen‐vacancy(NV~-)centers of diamond has excellent optical properties such as zero phonon lines observed at room temperature,stable luminescence and long coherence time.Especially,they have very special fine level structure,which can realize high-precision physical quantity detection and quantum control.Ultra-low concentration NV centers,especially single NV center,have attracted wide attention in the fields of photon entanglement,quantum regulation and so on.High concentration NV centers have been widely used in the field of physical measurement,such as temperature measurement,magnetic field measurement,ultra-high resolution imaging,high performance gyroscope and so on.There are usually two methods to prepare high concentration NV centers:nitrogen ion implantation and electron implantation.In this paper,the main method of preparing high concentration NV centers is electron injection and high temperature annealing.The fluorescence spectra of diamond NV color center samples were measured.Then ODMR spectra are measured by using a self-built optical detection magnetic resonance system.In addition,ODMR spectra of NV color center samples at high rotational speeds were also detected by a self-designed high-speed rotating device.The work of this paper is summarized as follows:1.Diamond samples with high nitrogen content were prepared by CVD method.Electron injection experiments were carried out using industrial high energy electron irradiation equipment.Stable high concentration NV center samples were prepared by high temperature annealing in nitrogen atmosphere and characterized by spectroscopy.2.The diamond samples with different NV centers were prepared by electron irradiation and annealing at variable temperature.Then the fluorescence spectrum of NV centers prepared under different conditions were measured and analyzed.The total fluorescence intensity of the phonon bands was obtained to characterize the concentration of NV centers.The relationship between NV center concentration and annealing temperature was analyzed.According to the variation of NV center concentration in different temperature ranges,three zones were proposed,i.e.suppression zone,diffusion zone and saturation zone.The Boltzmann model of NV center concentration and annealing temperature was fitted according to the experimental data,and the change rate of NV center concentration near 780 degrees Celsius was the fastest.3.Barnett effect refers to the phenomenon that a non-charged object generates a magnetic field through its own rotation.The diamond sample with NV center belongs to paramagnet,and owing to its special energy level structure,splitting ODMR signals can be generated under magnetic field conditions.We believe that the existence of Barnett field can be demonstrated by ODMR Valley splitting of high-speed NV center samples rotating around axes.A high-speed rotating device was designed and ODMR signal was measured at high rotating speed.It was found that the ODMR signal had a splitting tendency,but no complete splitting was found.4.Steady-state absorption,emission,and time-correlated single photon counting(TCSPC)method were utilized to study the spectroscopic properties of linear and multi-branched bithiazole-based derivatives in solvents(toluene,chloroform and dichloromethane)at room temperature.The absorption,photoluminescence properties and photodynamic process of solvent polarity for single-branch and multi-branch thiazole derivatives were discussed.