Interacting dark states with enhanced nonlinearity in an ideal four-level tripod atomic system

Abstract

We present an experimental system to generate large cross-phase modulation ͑XPM͒ in cold rubidium atoms. By using an efficient state-preparation technique in the 87 Rb D1 line, an ideal four-level tripod-type atomic system is formed, which generates large cross-Kerr nonlinearity via interacting dark states in this system. The induced phase shift due to XPM for the probe beam is measured for different trigger beam intensities, which is the key to achieving conditional quantum phase gates and many other applications in quantum information processing.

Controlled multi-wave mixing via interacting dark states in a five-level system

“…Then the doubly-dressedstates in cold atoms were observed, in which triple-photon absorption spectrum exhibits a constructive interference between excitation paths of two closely spaced, doubly-dressed-states [6]. A similar result was obtained in the inverted-Y system [7] and double-Λ system [8]. In this work, we go further to theoretically study, in a five-level system with three possible dressing fields, three types of dual-dressing (nested, sequential and parallel) schemes and precisely predicted the splitting of dark states resulting in five absorption peaks.…”

Polarized dependence of nonlinear susceptibility in a single layer graphene system in infrared region

“…In nonlinear optics, due to significant role of Kerr nonlinearity in some important phenomena [26,27], it is favoraitable to have giant Kerr nonlinearity in low light intensities [28]. Recently it has been shown that the giant enhanced Kerr nonlinearity in multi-level atomic systems with zero linear absorption can be possible by different mechanisms [29][30][31][32][33][34][35][36][37][38]. Niu et al investigated giant Kerr nonlinearity via double dark resonances in a four-level atomic system [35].…”

Dynamics of Entanglement between Moving Four-Level Atom and Single Mode Cavity Field

“…Recently, some authors have paid attention to study the four level systems under various configurations interacting with cavity modes. Many schemes of the four-level atomic systems have been studied and also visualized [12][13][14][15][16][17][18][19][20]. Moreover, a system consists of a four-level atom interacting with a single mode cavity field when the atom is prepared initially in a momentum eigenstate has been studied [16,19].…”