Research On Highly Sensitive Solid-state Atom Spin Magnetic Sensing Method Based On Microwave Dual Channel Modulation And Demodulation

Magnetic field measurement is widely used in deep-sea exploration,geological exploration,biomedicine and other fields.At the same time,it faces the demand of high precision and high sensitivity.In recent years,the classical theory of quantum technology has promoted the innovation of communication,computing,navigation and other technologies,giving the possibility of breaking the limit of physical quantity sensing measurement.The traditional gaseous atom magnetic sensing has high sensitivity,but it is difficult to miniaturize.The solid-state atom spin magnetic sensing takes into account the advantages of high precision and miniaturization,and has become the main trend of the application and development of ultra-high precision atomic spin sensing technology.At present,the precision of solid-state atom spin magnetic sensing has reached the order of 1p T.However,due to the temperature dependence of diamond nitrogen vacancy color center,there is temperature noise in magnetic sensing,which makes it difficult to improve the precision.Therefore,a highly sensitive solid-state atom spin magnetic sensing method based on Microwave two-way modulation and demodulation is proposed to reduce the influence of temperature on solid-state atom spin magnetic sensing.Firstly,this paper introduces the research status of diamond nitrogen vacancy color center magnetic sensor and the research status of diamond nitrogen vacancy color center temperature noise.Based on the Hamilton equation,the magnetic sensing model of diamond nitrogen vacancy structure is established,the magnetic sensing mechanism of diamond nitrogen vacancy structure is studied,and the optical detection magnetic resonance technology is introduced,which can be used to extract the electron spin state in diamond nitrogen vacancy structure.Secondly,based on the characteristics of energy level drift caused by magnetic field and temperature,a two-way magnetic sensing method is proposed.Through the feedback between the two spin information,the differential cancellation of temperature noise is realized at the same time.A two-way system scheme is designed for this method.The microwave is frequency modulated by applying different frequency modulation signals,and the red light signal is demodulated respectively to realize the separation of the two spin states.PID frequency locking technology is used to lock one of the spin states,and its drift is negatively fed back to the other spin state to realize common mode cancellation of temperature noise.Finally,a two-way test platform is built to test the microwave antenna,the separation and synchronization of spin states.The modulation parameters are optimized so that the slopes of the two demodulation curves tend to be consistent.Through the magnetic sensing performance test of the dual system,it is found that the magnetic sensing sensitivity of the dual system is increased from 1.24m V/n T to 1.24m V/n T,which is 1.93 times higher than that of the single system,and the shot noise limit is 13.05 p T/Hz^1/2.In addition,when the diamond surface temperature is increased from 25?to 50?by using non-magnetic heating chip,the temperature noise suppression effect is increased by 11.09 times.In this paper,the exploration and work on the problem of temperature noise in nitrogen vacancy atom spin magnetic sensing are carried out.The high sensitive solid-state atom spin magnetic sensing method based on microwave two-way modulation and demodulation can suppress the temperature noise in the magnetic sensing system and help to further improve the sensing accuracy of solid atom sensors.