Research On The Effect Of Magnetic Field On Transmission Spectra Of Circularly Polarized Light

In practice, we always need to measure weak magnetic fields, such as bio-magnetic fields detection used in medical domain, the magnetic space detection based on satellite in the military field, landforms surveys, material defect detection, hydrocarbon resources exploration, underwater magnetic target position fixed, and archaeology and so on. So there are many methods of measurement in weak magnetic field now. However, the measurement accuracy is not the same. With the development of science and technology, quantum optics is also advancing rapidly. The method of light and atoms interacting to measure the magnetic field has also been widely promoted.The article is mainly measuring the magnetic field by the studying of the circularly polarized light transmission spectrum which is in magnetic field. This method of measuring is different from the conventional magnetometer. when the unknown magnetic field is fixed,resonance will occur at different location by scanning the vertical magnetic field. We can realize the measurement of weak magnetic fields by transmission or absorption spectrum.Namely that we can measure weak magnetic fields by transmission or absorption spectrum .The study is carried on from four aspects.The first part describes the process of interaction between light and atom and shows its many applications in terms of measuring the magnetic field. With further researching,we introduced some interesting phenomenon about the interaction of atoms with light ,which can stimulate the interest of research. At last we put forward this topic research content, purpose,significance and structure arrangement.The second part introduces the theory of the interacting of atom with light and magnetic field. We study the Cs atoms under the condition of the external magnetic field with the interaction of light. The characteristics of the Cs atoms, Zeeman Effect of Lamor procession and alkali metal atoms in Lamor procession are described briefly. Meanwhile, the introduction of the semi-classical theory of atoms interacting with the light field is mentioned. We also deduced density matrix equations of motion by the Schrodinger equation.In the third part,we describe the treatment methods in the present of transverse and longitudinal magnetic field respectively which can be solved by choosing different directions quantum axis. Subsequently, we may set z-axis as quantum axis,describing the Hanle configuration which is scanning the longitudinal magnetic field in the vicinity of zero magnetic field, fixing the transverse field. In the presence of the transverse field, we have obtained the absorption spectrum of the resonant laser with ?+ polarization. Then we analyze the physical principles from spectrum.The last part, we research the population distribution of 87Rb atom with ?+ circularly polarized light in magnetic field. And we analyze the absorption spectrum in the transverse and longitudinal magnetic fields. From the theoretical calculations, we get a new method of measuring the magnetic field which will be able to apply in magnetometer in the future.