Optical Signatures of Coupled Quantum Dots

An asymmetric pair of coupled InAs quantum dots is tuned into resonance by applying an electric field so that a single hole forms a coherent molecular wave function. The optical spectrum shows a rich pattern of level anticrossings and crossings that can be understood as a superposition of charge and spin configurations of the two dots. Coulomb interactions shift the molecular resonance of the optically excited state (charged exciton) with respect to the ground state (single charge), enabling light-induced coupling of the quantum dots. This result demonstrates the possibility of optically coupling quantum dots for application in quantum information processing. S emiconductor approaches to quantum information can leverage the industry_s vast technological infrastructure and inte-grate with existing information and communi-cation technologies. Quantum dots (QDs) are an attractive host for storing a quantum informa-tion bit (qubit), because their atom-like proper