Chromatic aberration. Animation showing the effects of wavelength on diffraction, an effect known as chromatic aberration. The index of refraction of materials such as lenses depends on the wavelength. Thus, the angle of light diffracted by a single glass lens is different for different colours and each wavelength has a different focal point. This animation starts with many red, green and blue photons initially located in the same plane resulting in white light. When passing the lens, the diffraction angle increases from red via green to blue causing different focal points, the blue one closer to the lens than the green and red one. This produces concentric coloured rings displaying the spectrum of visible colours.