We demonstrate direct control over the level of lateral quantum coupling between two self-assembled InGaAs/GaAs
quantum dots. This coupled system, which we also refer to as a lateral quantum dot molecule, was produced using a
unique technique which combines molecular beam epitaxy and in-situ atomic layer etching. Atomic force microscopy
measurements show that each molecule consists of two structurally distinct dots, which are aligned along the [1-10]
direction. Each molecule exhibits a characteristic photoluminescence spectrum primarily consisting of two neutral
excitonic and two biexcitonic transitions. The various transitions have been investigated using micro-photoluminescence
measurements as a function of excitation power density, time, and applied electric field. Photon statistics experiments
between the excitonic emission lines display strong antibunching in the second-order cross-correlation function which
confirms that the two dots are quantum coupled. Cascaded emission between corresponding biexcitonic and excitonic
emission has also been observed. Using a parallel electric field we can control the quantum coupling between the dots.
This control manifests itself as an ability to reversibly switch the relative intensities of the two neutral excitonic
transitions. Furthermore, detailed studies of the emission energies of the two neutral excitonic transitions as a function of
parallel lateral electric field show a clear anomalous Stark shift which further demonstrates the presence of quantum
coupling between the dots. In addition, this shift allows for a reasonable estimate of the coupling energy. Finally, a
simple one-dimensional model, which assumes that the coupling is due to electron tunneling, is used to qualitatively
describe the observed effects.