What wavelengths of light drive photosynthesis?

The pigment called chlorophyll a, which is present in most plants, is what allows light to be absorbed.

Since chlorophyll-a efficiently absorbs these wavelengths, photosynthesis peaks at approximately 450 and 650 nm, which correspond to the violet, blue, and red regions of the visible spectrum.

However, because extra absorption is provided by accessory pigments like carotenoids and xanthophylls, photosynthesis still happens at wavelengths between 500 and 600 nm.

Visible light, or wavelengths between about 400 and 700 nanometers, is the main source of energy for photosynthesis. Among these, blue light (about 450–495 nm) and red light (about 620–750 nm) are the most useful for photosynthesis. Chlorophyll and other pigments in the chloroplasts of plant cells absorb these wavelengths, using the energy to convert carbon dioxide and water into glucose and oxygen.