Electromagnetically Induced Grating In Multi-level Atomic System

Quantum coherence has attracted extensive attention of many researchers in thefield of the interaction between light and atomic system. The optical properties of aninteraction medium can be modified and controlled by interference with a strongcoupling field (either a traveling or standing wave field). Thus, the absorptioncoefficient and refractive index of the medium will be also changed. Then two typicalatomic coherence effects can be generated: electromagnetically induced transparency(EIT) and electromagnetically induced grating (EIG).In this paper, the EIG in three-level and six-level Λ type atomic system isdiscussed emphatically based on the EIT. The main content is:1、Calculated and simulated the EIT in the three-level atomic system, analyzedthe influence of each parameter to the transparent window by drawing figures. Andalso analyzed the change of the EIT with the Doppler effects; On the basis of EIT, wealso simulated the EIG in the three-level atomic system by using the standing wavefield instead of the traveling wave field. In order to obtain a better first-orderdiffraction efficiency, we also analyzed the influence of each parameter to the EIG.2、Expanded the energy level to the six-level atomic system. We drew EIG figureby analyze the influence of each parameter to the first-order diffraction efficiency andselect appropriate values. In order to realize a better EIG, we compared the efficiencyof phase diffraction grating, amplitude diffraction grating and hybrid diffractiongrating in the six-level atomic system with that in the traditional three-level atomicsystem.3、Calculated and analyzed the EIG in the same six-level system except theincident light field is placed in the energy levels of different from the case of above.Same as above, we drew the EIG figure and observed the grating diffraction. At the last, we discussed and compared the efficiency of grating diffraction in the threecases.The results showed that we can not only realize the EIG phenomenon in the six-level atomic system, but also the first-order diffraction efficiency is higher than that ofthe traditional three-level atomic system, this work can provide a theoretical basis forrelated experiments and realize EIG in a more complex level atomic system.