The dispersion of white light happens because the angle of refraction of lights of different colours is different while passing through the transparent medium. For example, ...

Learn about the spectrum of colours found in visible light, how to split white light and the primary and secondary colours of light in this guide for KS3 physics students aged 11-14 from BBC Bitesize.

To do this, the team used so-called sign-alternating-dispersion waveguides. The waveguides are designed to control the dispersion of light by alternately widening and narrowing the beam of light.