The Key Technology Of Magnetic Field Measurement Based On Microwave Modulated Solid-State Spinning Ensemble NV~-Centers

Solid-state spin magnetometer based on ensembles of NV~-centers is a new weak magnetic field measurement technology,which is developed by using the spin resonance characteristics of diamond NV color center,generating energy level splitting under external magnetic field,combining quantum manipulation,optical-spin interaction,weak signal detection and other technologies.Since the spin state of NV~-centers can be initialized,read out and controlled by microwave field at room temperature,NV~-center magnetometer can detect magnetic field with high sensitivity and spatial resolution at room temperature,which has broad application prospects in the field of weak magnetic field measurement.The sensitivity of solid-state spin ensembles of NV~-center magnetometer can be effeted by factors,which involved in the number of sensing spins(N),concentration of NV~-center(C),fluorescence collection efficiency,coherence time,the method of memagnetic field calculation and so on.In this paper,a series of key technologies of the microwave modulated solid-state spin ensembles of NV~-cente magnetometer are studied,such as characterization concentration in two and three dimensions,technique of microwave modulation and so on.The main research contents are as follows:Firstly,the ODMR measurement static magnetic field,Ramsey time series measurement DC magnetic field and Spin echo measurement of alternating magnetic field mechanism are studied theoretically.In addition,the sensitivity of magnetic field measurement and its influencing factors of these methods are elaborated,discussed and analyzed in detail.Besides,several ways to improve the sensitivity of NV~-magnetometer are given,which provides a theoretical basis for achieving the high sensitivity of ensembles of NV~-center magnetometer.Secondly,the method and realization of concentration of ensembles of NV~-characterization in two-dimensional and three-dimensional the growth law of ensembles of NV~-center are studied,which lays a foundation for the follow-up research group to carry out the controllable preparation of high concentration NV color center and high sensitivity of ensembles of NV~-center magnetometer.Thirdly,the principle of ensembles of NV~-cneters magnetometer based on sine-wave modulation and rectangular-wave modulation technology is derived and compared theoretically.The ensembles of NV~-cneters magnetometer based on microwave modulation technology is built independently,and the optimal parameters of the modulated signal are determined experimentally.Under the optimal experimental parameters,the sensitivity,bandwidth and noise spectral density of the ensembles of NV~-cneters magnetometer based on square wave modulation and sine wave modulation are studied.Finally,the magnetic sensitivity of the ensembles of NV~-cneters magnetometer based on microwave modulated method reached 9.4nTHz.