System Design Of Optical Pump Magnetometer With Rubidium Atom

Magnetic field measurement is widely used in the area of medical diagnosis,national defense and military,mineral exploration,historical relic and archaeology,geophysics,and other related applications.However,because of the limitations form the inherent defects of existing magnetometer systems,such as high cost,high complexity,high power consumption and low sensitivity,it is difficult for them to meet the growing demand of magnetic field measurement applications.For the problems in the application of magnetometer,a kind of rubidium atomic magnetometer system is designed,which has advantages of high sensitivity,low power consumption,simple installation and good temperature adaptability,which can satisfy with the requirements of medical and military applications.Based on the physical principle of rubidium atomic optical pump magnetometer,a rubidium atomic optical pump magnetometer and the corresponding detection circuit are designed,based on the physical theories of rubidium atom transitions,energy level structure,as well as the optical pumping effect and magnetic resonance effect.Finally,the performances have been verified.The main work of this paper includes the following:(1)Design of optical path and hardware system.Using high-power tunable semiconductor lasers as the light sources,the optical path of magnetometer system is designed.By designing the hardware system,the magnetometer signal detection and analysis is implemented.The system includes the design of FPGA main control unit,the design of Radio-Frequency(RF)signal,the design of Direct Current(DC)magnetic signal to be measured,the design of data acquisition system,the design of man-machine interaction system,and other related systems.(2)Signal analysis and the implementation of detection algorithm.By filtering the noise of the output signal of detectors,the Butterworth filter is employed and simulated by MATLAB.The influences of the modulation signal on the spectral line and the frequency modulation curve are analyzed.Afterwards,three algorithms of finding the resonant frequency are proposed and compared.The upper monitor software is completed and the signal output is displayed.(3)Debug of module function and system verification: The various modules of the system were debugged and results are obtained respectively,including the data acquisition module,the RF signal output module,the DC magnetic field output module and the USB information interaction module.By simulating the magnetic field,the whole system is jointly debugged,what’s more,the data and the waveforms are recorded.Moreover,the debugging results are analyzed.Therefore,the feasibility of the system design and the application value of the system are verified.