Controllable twin laser pulse propagation and dual-optical switching in a four-level quantum dot nanostructure

Abstract

We investigate control of the propagation dynamics of weak twin laser pulses and propose a dual-optical switching scheme in four-level semiconductor quantum dots of diamond configuration. It is shown that the propagation dynamics of the two probe pulses depend not only on the intensity of corresponding control field in each cascade transition path but also on the relative intensities of the two control fields. This property provides the probability for realizing all-optical switching in the quantum dots. Possible all-optical switching operations for any one of the probe fields or both probe fields simultaneously with the same or adverse switching status can be realized by modulating the corresponding control fields. In addition, the relative phase of the laser fields also influences the switching operation and can be used to realize optical switching, which is also discussed in the paper.