Short pulses propagation in multilevel atomic media

Abstract

Abstract. We investigate short pulses propagation through multilevel atomic vapors. The medium is composed of an ensemble of four atomic levels generated by the hyperfine structure of the D 1 transition in Rubidium-87 atoms. The pulses are resonant to their respective optical transitions, in order to have a well-defined pulse area definition. We discuss local stabilization of the pulse area with or without energy stabilization and as a function of the prolonged distance. Furthermore, we explore some new features for the propagation dynamics in multilevel atomic media which are beyond the traditional framework of McCall and Hahn area theorem and self-induced transparency.

Graph Entropy Associated with Multilevel Atomic Excitation

“…We show that space-dependent von Neumann entropy, through SVD spectrum of eigenvalues, reveals space-dependent transitions for entropy due to different classes of transition matrices. We compare the space behavior of our previous results on area development and energy attenuation with those presented here, for space-entropy [9]. We conclude that space-entropy points out the area transitions from nearby 2nπ to nearby (2n − 1)π for the field v 14 (t).…”

“…Figures 4 and 5 show the spikes with maximum-entropy and minimum-entropy. We compare the behavior of space-dependent entropy in Figures 4 and 5 with the space-dependent behavior for the area of the pulses and its energies obtained in [9]. The initial areas are the same in both cases with the same shapes as well as pulse durations.…”

“…Finally, we have chosen that initially all the excitation pulses have the same area θ 0 = 7.8π. The pulses are resonant to their respective dipole-allowed transitions in order to have a well defined area [9].…”

“…Therefore, SVD-entropy for A+F remains finite at big distances. Figure 5 presents the results when we do some rearrangement of elements in M 6 (t; z) matrix, where we move the field components to the last two columns in Equation (9). The difference in SVD-entropy for the two transition matrix is small for big distances where the atomic contribution to entropy is small.…”