A programmable dopant fiber includes a plurality of quantum structures formed on a fiber-shaped substrate, wherein the substrate includes one or more energy-carrying control paths, which pass energy to quantum structures. Quantum structures may include quantum dot particles on the surface of the fiber or electrodes on top of barrier layers and a transport layer, which form quantum dot devices. The energy passing through the control paths drives charge carriers into the quantum dots, leading to the formation of "artificial atoms" with real-time, tunable properties. These artificial atoms then serve as programmable dopants, which alter the behavior of surrounding materials. The fiber can be used as a programmable dopant inside bulk materials, as a building block for new materials with unique properties, or as a substitute for quantum dots or quantum wires in certain applications.