Stationary and quasistationary light pulses in three-level cold atomic systems

Abstract

We have studied stationary and quasi-stationary signal light pulses in cold -type atomic media driven by counterpropagating control laser fields at the condition of electromagnetically induced transparency. By deriving a dispersion relation we present spectral and temporal properties of the signal light pulse and a significant influence of atomic decoherence on the coupled stationary light pulses for spatial splitting. Finally we discuss quasi-stationary light pulse evolution characterized by frozen spatial spreading for a robust coherent control of slow light pulses. PACS numbers: 42.50.Dv, 42.50.Gy, 03.67.Mn Introduction Quantum coherence control and deterministic manipulation of light pulses have become a topical issue in optics and optical quantum information science. Herein, using electromagnetically induced transparency (EIT) effect [1] is one of the promising tools for the coherent control of weak light fields even in a single photon level [2,3]. This technique is intensively elaborated for various applications of EIT-based quantum memories [4,5] and generation of nonclassical light fields [6].EIT-based quantum coherence control of weak lights is a strong candidate for ultralow power nonlinear optics [7] applicable to quantum information science such as implementation of two-qubit gates in the optical quantum computing [8][9][10][11][12][13][14]. Using stationary light pulse (SLP) concept proposed recently under the EIT condition [15][16][17][18][19][20] seems to be especially prospective for this purpose due to prolonged lifetime of the slow light pulses in the atomic media. The SLP coherent control with two counterpropagating light fields has been initially demonstrated in a hot atomic gas [15] and in solids [21]. Later this basic scheme was studied for the cold atomic systems in a series of works [22][23][24][25][26][27][28][29][30][31].Herein, the two counterpropagating control light fields lead to the excitation of many spatial gratings and long-lived atomic coherences [22,23,25]. The coherence gratings can results in the signal light dynamics of splitting the input light pulse into two counter-propagating light pulses [22,[24][25][26]29].Recent numerical studies [27][28][29] of nonadiabatic effects in SLP dynamics have revealed strong negative influence of the multiply excited coherence gratings on the SLP [30][31]. However the spectral and temporal properties of SLP remains insufficiently elaborated for SLP outside of the

Transmission and reflection spectra of a Raman induced grating in atomic media

“…Using (10) and (11), we obtain (12) (13) Correspondingly, the energy transmission and reflection coefficients and R = can be written as and .…”

“…In this case, the boundary conditions take the form of those for the perfectly matched layer of thickness L [18]: , , where is the amplitude of the incident probe wave. With these boundary conditions, the solutions of (7) and (8) can be represented as (10) ,…”

“…Such structures can lead to unusual quantum-optical phenomena. For example, they can give rise to tunable band gaps [4,7,8], generation of stationary pulses [9,10], squeezing of probe pulse [4], tunable reflection (controllable mirror) [11], and light pulse splitting [12].…”

Coherent manipulation of the Raman-induced gratings in atomic media

“…When a standing-wave coupling field interacts with a three-level atomic system, the dispersion and absorption of a probe laser beam in an atomic medium is modulated spatially by the standing-wave coupling field. It has been proposed to induce spatially periodic quantum coherence for generation of a tunable PBG [6][7][8][9][10] and dynamic generation of stationary light pulses [11][12][13]. These structures are also referred to as electromagnetically induced absorption gratings (EIAG) [14] or electromagnetically induced gratings [15].…”

Dynamical observations of self-stabilizing stationary light

“…In fact, true standing wave control fields can cause unwanted coupling between counter-propagating fields and additional decay of the SL pulse [25,26,27,28]. The behaviour of EIT stationary light is well understood [29,30,31,32,33,34,35,36,37], and the interaction between SL and a stored light pulse has been demonstrated [38].…”