Studies On Electromagnetically Induced Transparency Of Rubidium Atom In Magnetic Field

The study of the interaction between light and matter is a basic research field of modern physics and material science.Electromagnetically induced transparency?EIT?has attracted much attention with a wide range of potential applications,such as light storage,high-precision measurement,magnetometer and atomic clock,and so on.EIT is a kind of nonlinear optical effect of the light-matter interaction,which makes the medium into a system with high transmission rate,deep change of dispersion and large non-linear effects.In addition,Rydberg atoms possess many unique atomic properties compared to the normal atoms,such as large atomic radius,electric dipole moment and polarization,and strong dipole-dipole interaction,which properties can also be altered by external fields.This research has significance in science and important application values,for example,quantum storage,quantum computing,and so on.In this dissertation,we excited the atom to the Rydberg state by two-photon resonance,forming a ladder-like EIT system.We studied the nonlinear optical properties of Rydberg atoms and got the high-resolution splitting spectra in an external magnetic field at room temperature.The main research contents of the paper are as follows:?1?The investigation of the?-type EIT of the D₂ line of Rubidium atoms in no magnetic fields.We measured the linear and nonlinear optical properties of the multi-level?-type EIT between the ground state 5S_1/2 and low excited 5P_3/2 state in no magnetic field.And we used the spectral decomposition and synthesis techniques to study Doppler velocity selective optical pump effect of the complex multi-level system in room-temperature.Taking into account these physical impacts,our theory can reproduce experimental observations with high accuracy.?2?The investigation of the?-type EIT of the D₂ line of Rubidium atoms in external magnetic fields.Firstly,we studied the effect of the buffer gas on the?-type EIT multi-energy level line,and selecting the appropriate gas pressure we completely eliminated the resonance peaks due to the velocity selective optical pump effect,and then obtained the high-resolution EIT spectra related only to the ground state,upon which we further investigated the Zeeman splitting of the EIT resonance in external magnetic in high resolution.The magnetic field we applied is either paralleled or perpendicular or even with any angle to the light propagation direction.Based on the EIT dispersion theory and the Hamiltonian of Zeeman interaction in magnetic field,we constructed a simulation model,which can fully explain the experimental observations well.?3?The investigation of the ladder-type EIT of ground state-1st excited state-high Rydberg state of Rubidium atoms in magnetic field.The Rubidium atoms are excited to the high excited Rydberg states via the double-resonant optical pumping effects,i.e.,5S_1/2?5P_3/2?nS/nD.We observed a high resolution spectrum with full width at half maxima?HWFW?of 3MHz in room temperature,and measured the fine structure of Rydberg states.Then,we investigated the Rydberg EIT splitting spectrum of nS or nD states with different polarization combinations of probe light and coupling light in magnetic field.Due to the wavelength mismatching effect and so many Zeeman sub-levels included,the observed splitting spectral were very complicated.We proposed a theoretical solution that combines energy level splitting and EIT dispersion.The frequency position and intensity of the split peaks were given by solving Hamiltonian equations including Zeeman sub-level interactions in magnetic field.And the EIT dispersion theory was used to synthesize the spectral curves.The simulation results explained well the EIT split spectrum observed in the experiment,as well as the additional magnetic field induced state mixing lines.This paper combined the EIT technique to accurately study the external field effect of the high Rydberg state of Rubidium atoms.In the next step,we will use the EIT technology to study the dipole blockade effect of the Rydberg atomic ensemble and realize the manipulation of the atomic quantum state,and promote the research of all-optical quantum devices.