Direct observation of optical excitation transfer based on resonant optical near-field interaction

This article reports the direct observation of longdistance optical excitation transfer based on resonant optical near-field interactions in randomly distributed quantum dots (QDs). We fabricated optical excitation transfer paths based on randomly distributed QDs by using CdSe/ZnS core-shell QDs and succeeded for the first time in obtaining output signals resulting from a unidirectional optical excitation transfer length of 2.4 μm. Furthermore, we demonstrate that the optical excitation transfer occurs via the resonant excited levels of the QDs with a comparative experiment using nonresonant QDs. This excitation-transfer mechanism allows for intersecting, non-interacting nano-optical wires.