Electromagnetically Induced Transparency And Electromagnetically Induced Absorption In 87Rb Bose-Einstein Condensate

The quantum coherence effect has produced many novel physical phenomena in the field of atomic physics.This paper focuses on the electromagnetically induced transparency based on atomic destructive interference and the electromagnetically induced absorption based on constructive interference.The novelty lies in that we use the Bose-Einstein Condensate?BEC?as a medium for the interaction of laser and atoms.BEC is a peculiar material state,which has many advantages that distinguish it from the conventional matter state.It can artificially control the interactions between atoms,the binding potential structure,different spin components,and the number of atoms.Many interesting physics topics,such as optical lattices,topological insulators,and problems of superconductivity,can be studied on the platform of Ultra-cold atoms as quantum simulation.This dissertation mainly focuses on the study of the interaction of laser and⁸⁷Rb BEC produced in optical dipole trap on the Ultra-cold atomic system.The paper firstly introduces the⁸⁷Rb atomic energy level structure,including the atomic fine structure,hyperfine structure,and the energy level splitting caused by the Zeeman effect in the magnetic field.Based on this,there are two types of force for atoms in the laser field-scattering force generated by absorbing photons and the dipole force generated by detuning laser in an inhomogeneous laser field.Then,the design of magneto-optical trap was introduced for atoms of laser cooling and trapping.The working principle of the magneto-optical trap was briefly described,as well as the concept of a Magnetic Trap for trapping cool atoms in the experiment.We illustrate the conversion from a Quadrupole Trap to a Quadrupole Ioffe Trap and influences of using high-power far-detuning green laser to block zero point of magnetic field in the Magnetic Trap.Secondly,the paper describes the various systems in the⁸⁷Rb Bose-Einstein Condensate experiment.By summing up the experience of previous generations,we finally chose the current two-level magneto-optical trap system for laser cooling and trapping of atoms.The experiments were briefly introduced for different lasers required for atomic cooling.In the laser system,we explain the Saturated Absorption Stabilization frequency technology in detail.When the Magnetic Trap is loaded,we use high-power far-detuning green laser to block zero point of magnetic field and avoid the loss of the atoms.The cold atoms in the Magnetic Trap are subjected to RF evaporation from the low-field approaching state to the high-field approaching state,then escape outside the magnetic trap,which further reduces the number and temperature of atoms.Finally,Optical Dipole Trap are experimentally constructed to trap atoms,and the master computer system was used to control the depth of the Optical Dipole Trap through the feedback circuit.Finally,we get the Bose-Einstein condensate of⁸⁷Rb atom after evaporation cooling in the Optical Dipole Trap.Finally,a typical?-type three level energy structure on⁸⁷Rb D1 line is selected as a model for electromagnetically induced transparency and electromagnetically induced absorption.Combined with the Saturated Absorption Stabilization frequency and the Optical Phase-Locked Loop,we create experimentally the coupling field and the probe field.By scanning the frequency of the probe laser,we draw the lines of the two-photon detuning and the number of remaining atoms,and observe experimentally the electromagnetically induced transparency and electromagnetically induced absorption.