Various aspects of the present invention relate to light-interacting components suitable for use in chips and other reactor systems. These components may include waveguides, optical fibers, light sources, photodetectors, optical elements, and the like. If waveguides are used, they may be fashioned out of any material able to transmit light to or from the reaction site. The chip may contain a reaction site having a volume of less than about 1 ml. In some embodiments, the chip may be constructed in such a way as to be able to support a living cell. The chip may be used for imaging or analysis, or the chip may be used to facilitate a chemical or biological reaction, which may be light-sensitive or light-activated in certain cases. Other facilitated reactions may include the production or consumption of a chemical or biological species. In some embodiments, the chip may include more than one component or component type, or more than one reaction site.