  Optical near-field interactions between nanostructured matter, such as
quantum dots, result in unidirectional optical excitation transfer when energy
dissipation is induced. This results in versatile spatiotemporal dynamics of
the optical excitation, which can be controlled by engineering the dissipation
processes and exploited to realize intelligent capabilities such as solution
searching and decision making. Here we experimentally demonstrate the ability
to solve a decision making problem on the basis of optical excitation transfer
via near-field interactions by using colloidal quantum dots of different sizes,
formed on a geometry-controlled substrate. We characterize the energy transfer
behavior due to multiple control light patterns and experimentally demonstrate
the ability to solve the multi-armed bandit problem. Our work makes a decisive
step towards the practical design of nanophotonic systems capable of efficient
decision making, one of the most important intellectual attributes of the human
brain.
