The invention relates to a diaphragm electrolytic cell, for the production of chlorine and caustic soda having superimposed modules, and a method for increasing the electrodic surface of a diaphragm electrolytic cell constituted by a module of interdigitated anodes and cathodes which foresees an additional cell module having the same geometry as that of the original cell. The beamforming elements are mounted in integrated circuits which bridge the junctions between adjacent circuit boards. A high-powered, intense laser beam is fired into the water. Further, at least one transparent surface of the cell container enables observation of the cell culture. Circuitry may electrically connect to the first source of light and the second source of light.