Far-red light

Far-red light is a range of light at the extreme red end of the visible spectrum, just before infrared light. Usually regarded as the region between 700 and 750 nm wavelength, it is dimly visible to human eyes. It is largely reflected or transmitted by plants because of the absorbance spectrum of chlorophyll, and it is perceived by the plant photoreceptor phytochrome. However, some organisms can use it as a source of energy in photosynthesis.^[1][2] Far-red light also is used for vision by certain organisms such as some species of deep-sea fishes^[3][4] and mantis shrimp.