Efficient electromagnetically induced phase grating via quantum interference in a four-level N-type atomic system

摘要

An electromagnetically induced phase grating controlled by spontaneous generated coherence (SGC) in a fourlevel N-type atomic system is studied. The results indicate that the diffraction efficiency of the phase grating is dramatically enhanced due to the existence of SGC, and an efficient electromagnetically induced phase grating can be obtained. A novel result is considerable improvement of the intensity of higher-order diffractions via relative phase between applied laser fields. Furthermore, it is found that the frequency detuning of the switching and coupling fields with the corresponding atomic transition, incoherent pumping, and the interaction length can improve the efficiency of the phase grating in the present atomic model.