Controllable gain, absorption and dispersion properties of an asymmetric double quantum dot nanostructure

We propose a method to control the gain, absorption and dispersion properties in an asymmetric double quantum dot nanostructure interacting with four optical fields. From numerical results, it is found that the gain, zero-absorption (transparency), normal dispersion and the anomalous dispersion can be achieved separately by modulating the intensities of two control fields or the relative phase of the applied fields. This approach allows substantial flexibility in the manipulation of light propagation between subluminal and superluminal.