Title:Left-handedness without absorption in the four-level Y-type atomic medium

Abstract:In this paper,three external fields interacting with the four-level Y-type atomic system described by the density-matrix approach is investigated .The results show that the left-handedness with zero absorption are this http URL the zero absorption property displays the possibility of manipulation with varying the phase and the intensity of the coupling field. The zero absorption property may be used to amplify the evanescent waves that have been lost in the imaging by traditional this http URL scheme proposes an approach to obtain negative refractive medium with zero absorption and the possibility to enhance the imaging resolution in realizing "superlenses".