Optically Induced Long‐Range Coupling Studies in a Single GaAs Laterally Coupled Quantum Dot

Abstract

Excitation intensity dependent time‐integrated/‐resolved photoluminescence measurements have been performed on a single GaAs laterally coupled quantum dot to understand the long‐range (over 30‐nm distance) optical couplings. When linearly polarized laser excitation is increased parallel to the lateral coupling direction , a coupled bi‐exciton, which comes from both quantum dots 1 and 2 of a coupled dot, emerges with a spectral redshift. Drastically different power factors are observed separately in two different localized excitons, and an extremely larger diamagnetic coefficient is measured from a coupled bi‐exciton. In addition, a decay time in coupled bi‐exciton is obtained that is nearly two times longer than those in localized bi‐excitons when the excitation intensities are increased. The correlations from power‐dependent photoluminescence intensities and decay rates are attributed to exciton transfer between the two quantum dots based on dipole–dipole interactions.