Optical precursors with tunneling-induced transparency in asymmetric quantum wells

Abstract

A scheme for separating optical precursors from a square-modulated laser pulse through an asymmetric double Al x Ga 1−x As/GaAs quantum-well structure via resonant tunneling is proposed. Destructive interference inhibits linear absorption, and a tunneling-induced transparency (TIT) window appears with normal dispersion, which delays the main pulse; then optical precursors are obtained. Due to resonant tunneling, constructive interference for nonlinear susceptibility is created. The enhanced dispersion in a narrow TIT window is about one order of magnitude larger than that of the linear case. In this case, the main pulse is much delayed and the precursor signals are easier to obtain. Moreover, the main pulse builds up due to the gain introduced by the enhanced cross-nonlinearity.

Coherent control of optical precursors in a warm atomic system with Doppler effects

“…EIT [11], self-induced transparency [12], tunneling induced transparency [13], etc.). Experiment works also have demonstrated this transient behavior through GaAs [14], mercury [15] and cold atoms [16][17][18].…”

Enhanced gain and narrow linewidth of an optical cavity by the Doppler effect in a four-level atomic system

“…An additional control field with moderate strength drives transition |2 ↔ |4 with Rabi frequency Ω c . A similar system was widely used in quantum optical experiments, such as the giant Kerr effect [29][30][31], optical switch [32][33][34], four-wave mixing [35,36], collective field entanglement [37], and optical precursors [38,39], etc. The dynamics of the atomic system can be described using the density-matrix approach aṡ…”

Optical precursors with competing linear and nonlinear dispersions in quantum dot molecules

“…Simulation results show that its intensity could be enhanced by one order compared with the incident pulse. Previously, we proposed a scheme for separating optical precursors from an incident pulse [34], where the cross-Kerr nonlinearity showed normal dispersion and was only used to separate optical precursors from the delayed main signal. Here we focus on the competition of linear and nonlinear dispersions, which leads to the separation and enhancement of optical precursors.…”