Two-dimensional Electromagnetically induced grating in a microwave driven cascade-type closed-loop atomic system*

Electromagnetically induced grating (EIG) is a phenomenon similar to electromagnetically induced transparency (EIT) but creates with a control standing wave. Initially, EIG was proposed in a three-level Λ-type system [1] in which a transparent and opaque regions appear alternately in the atomic medium along the control field. If a probe field is made incident perpendicular to the above medium, then it acts as an amplitude grating. The same probe field also changes in the refractive index of the medium and it leads to Phase Grating. In the present work, we explore the impact of microwave field in a two-dimensional EIG using a cascade-type closed-loop atomic system. Our numerical analysis shows that the presence of microwave field leads to a spatial dependent amplitude suppression in the atomic system. We also observe that the microwave field can also dramatically enhances the high order diffraction of the probe field from the zeroth-order. Therefore the phase grating becomes more dominant in the presence of microwave field. We believe that the proposed system with microwave field can be used for designing a novel microwave sensing devices in the optical networking and communication.

[1] H.Y. Ling, et al., Phys. Rev. A 57,1338 (1998)