Controllable electromagnetically induced grating in a cascade-type atomic system

A controllable electromagnetically induced grating (EIG) is experimentally realized in a coherent rubidium ensemble with 5S1/2-5P3/2-5D5/2 cascade configuration. In our work, a whole picture describing the relation between the first-order diffraction efficiency and the power of the coupling field is experimentally presented for the first time, which agrees well with the theoretical prediction. More important, by fine tuning the experimental parameters, the first-order diffraction efficiency of as high as 25% can be achieved and a clear three-order diffraction pattern is also observed. Such a controllable periodic structure can provide a powerful tool for studying the control of light dynamics, pave the way for realizing new optical device.