A nanometer dimension light source includes a source of excitation and an active, electrooptic or chemilluminescent material such as crystalline anthracene. The material is introduced into a confined space having molecular dimensions or is shaped to a point of molecular dimensions. The material is surrounded by an insulator such as a glass pipette which also forms the confined space and which also serves as a reflector for radiation produced in the material. An electric field is imposed on the active medium, injecting holes and electrons which recombine to produce light within the small dimensions of the pipette.