Experimental And Theoretical Research Based On The Linearly Polarized Atomic Magnetometer

Magnetometry is widely used in many fields,for example,mineral exploration,geological detection,biomedicine and aerospace.Magnetometer based on the atom-field interaction has been realized and developed in the past half century,along with the better understanding of the interaction properties between light and atoms.At present,the sensitivity of atomic magnetometer is the highest in the whole world,which can reach even the scale of 0.1fT/(?).The atomic magnetometer can be used to measure near-zero magnetic field,non-zero magnetic fields,geomagnetic fields,scalar and vector magnetic fields,and it has a wide application prospect.Better understanding of the atom-field interaction is very helpful for people to improve the performance of the magnetometers.This thesis mainly focused on the theoretical and experimental research based on the linearly polarized atomic magnetometer The experimental system based on the basic principles has been built,and the way of measuring the magnetic field and sensitivity has also been learnt.The factors which may affect the magnetic field measurement have also been analyzed and explained.The main contents are as follows:1)The development of the magnetometers and the research status of the atomic magnetometry have been introduced.2)The polarization of light and the polarization of atoms are introduced.And by combining the visualization of the polarization,the orientation of the atomic polarization and the evolution of the atomic polarization in the magnetic field have been explained.3)A cesium atomic magnetometer has been built with both pump beam and probe beam being linearly polarized.In this process,the atomic spin relaxation and the inhomogeneity of the magnetic field have been analyzed.The nonmagnetic electrical heating has also been designed and realized.4)The magnetic resonance linewidth(MRL)is measured experimentally with pump beam and probe beam tuned to resonant to cesium D1 line 62S1/2F=4-62P1/2F=3 and D2 line 62S1/2F=4-62P3/2F=5.The experimental result is explained theoretically with a simplified atomic level model,which is built by us.5)The MRL,signal-noise ratio at the magnetic resonance frequency(SNR)and the sensitivity are all measured experimentally.In this experiment,the pump beam is resonant to cesium D1 line.The pump beam is resonant to 62 S1/2F=4-62 P1/2F=3 for direct pump and resonant to 62 S1/2F=3-62 P1/2F=4 for indirect pump.The experimental results are explained with a combination of the rate equation and the Bloch equation.6)The influence of probe intensity on the magnetic field measurement is analyzed with indirect pump beam.Both the experimental and theoretical results show that if the ground states of pump and probe are different,the spectrum of magnetic resonance can be fit with the Dual-Lorentz lineshape.In the end,two different vapor cells have been tested by using the direct pump beam,and the influence of the buffer gas on the magnetic field measurement has been analyzed.7)According to the experiments and the theoretical model we have been completed,the optimization of the system in the next step is proposed.