Polarization Modulation And Properties Of Electromagnetically Induced Grating In An Atomic System

Quantum coherence caused by the interaction between light and atoms is an important research direction in the field of optics.Among them,Electromagnetically induced transparency(EIT)and Electromagnetically induced grating(EIG)are typical physical phenomena in quantum coherence,which have attracted the attention of many physicists and have great research value and potential of development.Under the influence of the EIT effect,the absorption coefficient and refraction coefficient of the medium were changed.Based on the EIT,the phenomenon of electromagnetically inducted grating is formed by replacing the traveling wave field with the standing wave field with periodic variation,and the physical parameters affecting the diffraction efficiency of the detection field are explored.In this thesis,based on the theoretical calculation of electromagnetically induced transparency and electromagnetically induced grating effect,a kind of all-grating structure,electromagnetically induced polarization grating,is realized by adjusting the amplitude,phase,frequency and polarization of the light field according to the actually demand.Polarization-dependent multi-beam splitting is realized.Based on the theoretical study of electromagnetically induced transparency effect in rubidium atomic system with different level structure,the coupling standing wave field is used to replace the traveling wave field,so that the absorption rate of coherent light in atomic medium shows periodic change,and the electromagnetically induced grating phenomenon is realized.The coupling field was adjusted as orthogonal standing wave field to realize two-dimensional electromagnetically induced cross grating.The relevant images of electromagnetically induced grating were drawn according to the theoretical calculation results,and the factors affecting diffraction efficiency were analyzed to optimize diffraction efficiency.The influence of polarization regulation on electromagnetically induced grating effect is explored in atomic system.Through flexible regulation of coupled standing wave field,such as making the strongly coupled standing wave field acting on the medium have the same direction and different spatial period,one-dimensional electromagnetically induced polarization grating is realized.The direction of the coupled standing wave field is different from the spatial period,and the twodimensional electromagnetically induced polarization grating is formed.The first-order diffraction efficiency of the three-level atomic system can be increased to 25% by polarization modulation,and the two polarization components of the detection field can be separated in space,so that the two polarization components of the detection field through the medium can be decoupled,and one-dimensional and two-dimensional polarization detection light with different angles can be generated in the far field.In this thesis,based on the electromagnetically induced transparency,a research scheme of electromagnetically induced polarization grating is proposed.By adjusting the coupling field,the two polarization components of the detection field are decoupled.The research can be applied to the design of polarization beam splitter.This polarization correlation method has important potential application value in quantum information processing.