The dispersion relation of a material describes how the speed and behavior of a wave—like light—change with its frequency when traveling through that material.
In simple terms:
- It shows how different colors or frequencies of light move differently inside the material.
- In a dispersive material, the refractive index changes with the frequency of the wave.
- As a result, higher-frequency waves (like violet or blue light) and lower-frequency waves (like red light) do not travel at the same speed.
- The dispersion relation helps explain how and why light bends differently at each color, and why white light splits into a spectrum when it passes through a prism.
- This relation is important in physics and engineering because it helps us understand how waves spread out, bend, or get delayed in different materials.
So, the dispersion relation tells us how the material affects wave propagation, depending on the wave’s frequency or color.