Research On Optical Weak Magnetic Sensor Based On Single Beam

The magnetic field is one of the most essential and significant physical measurement quantities,as much as inertia and gravity.The accurate detection and measurement of magnetic fields,particularly the extremely weak magnetic field(below nT level),is effective for understanding the physical world.In the practical application of weak magnetic field sensors,more and greater demands have been made on its major parameters like sensitivity and volume of structure,given its important role in the fields of scientific research,national defense,bio-medicine,and industrial production.The magnetic field measurement of atomic magnetometers is mainly based on the measurement of the optical rotation angle – two laser beams are used for pumping and detection,respectively,and such structure generally has a large volume that cannot be reduced on the optical path so as to restrict the miniaturization of atomic magnetometers.To make a change in the detection principle,this paper integrates pump light with detection light and measures the magnetic field using a single beam,as a preliminary study of the structure of miniaturized magnetometers.The research content is mainly as follows:1.Presenting the research significance and background of this experimental project;discussing the progress and status of atomic magnetometer research at home and abroad;proposing the direction of further research.2.Describing the basic detection principle and concept of alkali metal atom magnetometers,including the internal structure and properties of alkali metal atoms in atomic magnetometers,the polarization of alkali metal atoms under the condition of optical pumping,and the spin-magnetic field interaction with the addition of the magnetic field;analyzing the schemes of single beam and double beam measurement by the Faraday method,respectively,based on the principle of optical pumping.3.Elaborating on relaxation in the cell: discussing three major types of relaxation:spin-destruction relaxation,spin-exchange relaxation,wall-collision relaxation;calculating simulated minimum theoretical values and conditions for each type of relaxation based on their cause and effect;examining the generation of spin-exchange relaxation free,discussing the effects on spin-exchange relaxation of various impact factors including temperature,magnetic field,and polarizability,and calculatingsimulated optimum values of each impact factor.4.Proposing and describing a scheme of measuring the optical power using a single beam to measure the vector magnetic field;conducting a theoretical analysis of the detection principle and a simulated analysis of the detection results.5.Setting up an experimental platform,including the experimental devices required to implement the scheme of measuring the optical power using a single beam to measure the vector magnetic field;describing the various devices and schemes in the experiment,including heating means,temperature control,and magnetic field building.