Light at work: past, present, future

Light is an essential ingredient of life as poetically expressed by W. Ostwald: “Life is a water mill: the effect produced by the falling water is achieved by the rays of the sun. Without the sun the wheel of life cannot be kept going”. Light is indeed at the basis of life not only because plants produce oxygen and carbohydrates through a rather complex process known as photosynthesis, but also because it sustains our body through the synthesis of vitamins, is responsible for the object’s colours perception, provides work, leisure, psychological equilibrium, and information, affects our alertness, comfort and emotional state, brings architecture, art, and fashion to life.