Study On Quantum Magnetometer Of Diamond Ensemble NV Centers

Nitrogen vacancy(NV)centers is one of the discovered light-emitting point defects of diamond.It has become a research hotspot in recent years because of its long spin coherence time at room temperature,optical spin state initialization,quantum spin manipulation and so on.Compared with other types of magnetometers,NV magnetometer has the advantages of high spatial resolution and less harsh measurement conditions.Its related sensor design has been widely studied in the fields of multi physical field measurement,biological probe,magnetic imaging,temperature imaging and so on.In this paper,the research trend and development status of atomic magnetometer are briefly introduced,and the research is carried out around the working mechanism,sensitivity analysis and integration of NV magnetometer.The specific work contents are as follows.Firstly,the basic concept and energy level structure of NV color center are introduced.Based on the sensing theory of NV color center,the principle of displacement detection is explored,which enriches the sensing theory of NV color center vibration detection.From the direction of magnetic measurement,the basic model of NV color center vibration sensing system is constructed.Lastly,the vibration range of the vibration source used in the experiment is 1.488 mm and the displacement noise sensitivity is 25.11 nm/Hz^1/2.Secondly,a portable high-sensitivity magnetometer based on micro confocal(CSPM)system is designed and tested.The design of this structure not only solves the problem of asynchronous microwave resonance transition in conventional integration,but also improves the difficulty of suppressing the noise of the integrated magnetometer.Finally,the volume of the integrated magnetometer was limited to 11 cm~3 and the detection sensitivity is as high as 37n T/Hz^1/2.Thirdly,a high-precision 2D integrated magnetometer module is designed and studied,which includes a signal amplification circuit to ensure the ultra-low noise of the signal.At the same time,by placing anti microwave shielding network and optimizing the interference distance,the interference effect of microwave on the amplification circuit is eliminated to the greatest extent.In addition,a fixed frequency optical detection method based on magnetic resonance(FF-ODMR)is proposed,which can detect the relationship between magnetic field and photoluminescence by scanning magnetic field at a specific frequency,and further analyze the sensitivity of magnetic noise based on fluorescence intensity.The NV magnetometer has a construction area of 7.12 cm~2,the magnetic field sensitivity is about 25.12 n T/Hz^1/2.