Laser Physics Letters

Ultra-slow propagation of light located in ultra-narrow transparency windows through four quantum dot molecules

Hamid Reza Hamedi

Published Jun 6, 2014• 26 citations

Abstract

This letter investigates the dispersion and absorption properties of a weak probe field in a multiple quantum dot molecule composed of four quantum dots. It is found that, by manipulating the electric field, the inter-dot tunneling coupling and the laser detunings, the transparency window as well as the positive derivative in the refractive index can be efficiently qualified. It is shown that switching from positive to negative dispersion or vice versa can be achieved by changing the tunneling couplings. Moreover, we realize that the width and the number of transparency windows can be properly controlled by adjusting the system's parameters. We show that this multiple QD medium can experience very narrow transparency windows accompanied by very steep positive dispersions. The effect of an incoherent pumping field on the absorption–dispersion properties of the QD molecule is then discussed. We note that tunneling is used in this QD system instead of coupling lasers.

DOI: 10.1088/1612-2011/11/8/085201

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