Solar radiation (SR) is the main driver of the planetary energy balance and it is essential in various areas of human activity. In the energy context, particularly in renewable energies, the broadband solar radiation is converted into useful heat or electricity. The interaction of the wavelengths of the visible spectrum of SR (daylighting or illuminance, L, 400-780 nm) with the photoreceptors of the human eye, allows to perceive the world and its colors, and it has influence on mood and circadian rhythms. Daylight is also essential for the improvement in the energy efficiency of buildings and visual comfort. . In agriculture, Photosynthetically Active Radiation (PAR, 400-700 nm) is the energy source to trigger photosynthesis which makes possible the production of food and biomass. Finally, Ultraviolet UVR (UV-A, 315-400 nm; UV-B, 280-215 nm) is responsible for a wide variety of photochemical reactions, especially its shorter wavelengths have deleterious effects in many biological systems.
