Phase And Amplitude Control Of Atomic Grating In A Three Level Closed Lambda System

We have theoretically studied the electromagnetically induced grating (EIG) in a three-level closed Lambda-type atomic system. The upper level is coupled to the two lower levels via a strong control and a weak probe field. In addition to these two optical fields a weak microwave field is also applied to couple the lower two levels. Our results show that the relative phase of the three fields in the presence of microwave field enhances the dispersion in the medium and consequently provides control over magnitude of the diffraction intensities. We have optimized the system parameters such as strength of the fields and interaction length to attain increased first order diffraction. Furthermore, we have also studied the effects of probe detuning on diffraction intensities. Interestingly, the probe detuning results in suppression of the zeroth order intensity while increasing the higher order intensities.