Phase Control of Group Velocity in a Doppler-Broadened Λ-Type Three-Level System

Switching between slow light and fast light by static magnetic field in a degenerate four-level atomic system at room temperature

“…The static magnetic field (B) is oriented parallel to the propagation direction of the laser fields to separate the ground state submagnetic levels through the Zeeman effect. Therefore, the Zeeman shift (∆ B ) of the ground state submagnetic levels is determined by [31]:…”

“…On this basis, extremely slow or superluminal light pulses were obtained in the EIT [7][8][9] or EIA [10][11][12] regime, respectively. In particular, some recent studies have shown that it is possible to switch between EIT and EIA modes [13] and thus can switch between fast light and slow light by external fields such as using microwave field [14], standing-wave field [15], Kerr field [16][17][18], coherent pump field [19,20], incoherent pump field [21][22][23], static magnetic field [24,25], or using other coherence effects such as spontaneously generated coherence [22,23,[26][27][28][29] and the phase of applied laser fields [30,31] and so on.…”

“…However, most of these works are applied to ultracold atomic media with the Doppler effect being ignored. A small number of other studies were performed at room temperature with the Doppler effect included [19,20,[31][32][33][34][35][36], which is needed for experimental and applied studies in practice.…”