Research On The Key Technology Of Sensitivity Optimization Of Ensembles NV Color Center Magnetometer

Because of its high sensitivity and high spatial resolution,the real-time detection technology of solid-state spin signal can be applied to the NV color center magnetometer.In recent years,it has been found that the concentration of NV color center,spin state,coherence time and fluorescence collection efficiency are the key factors of the magnetic sensitivity of the NV color center magnetometer.Therefore,this paper focuses on two methods of DC magnetic measurement and AC magnetic measurement.The main research contents are as follows:1.In order to achieve the measurement of solid-state electron spin magnetism,and to produce high-precision synchronous sequential pulse as the research goal,the pulse sequence generation module and data acquisition,storage and operation module based on LabVIEW and spincore are designed through the self built confocal optical platform,combined with the system software,to realize the synchronous operation between different instruments.2.In order to improve the noise limit of DC magnetic field,an optimization method of CW-ODMR spectrum of（110）plane bias magnetic field is proposed.The optimal shot noise limit is 557 pT（?） and the noise spectrum sensitivity is 4.3 nT（?） .A two-way microwave control module is designed to improve the contrast of Rabi oscillation signal and the utilization ratio of electron spin of NV color center.3.Designed the pulse sequence to realize the spin regulation experiment,combined with the hardware and software system,measured that the period of Rabbi oscillation of the ensemble NV color center is 193.7 ns.In addition,the decoherence time T₂ is about 170 ns through the spin echo pulse sequence experiment.Based on the method of quantum control,the sensitivity of the platform system is 0.8 pT（?）.In this paper,the technology of collimation of bias magnetic field in the direction of crystal axis of NV color center[110]is proposed,which is used to suppress the noise of DC magnetic field detection of NV color center.The quantum control technology is optimized to test theπpulse of Rabi oscillation of NV color center,which lays a foundation for the subsequent precise magnetic measurement of NV color center.