Photonic crystal

A photonic crystal is like a special kind of material that can control the way light travels through it. Think of it like a maze for light! Just like how you might have played with a maze game where you move a marble through different twists and turns, a photonic crystal has tiny structures that can make light change direction in a similar way.

These tiny structures are like tiny bumps and holes in the material, arranged in a pattern. Think of it like the bumps and grooves in a record - they are arranged just so to create a certain sound. In a photonic crystal, the pattern of tiny bumps and holes are arranged just so to affect how light moves through the material.

Now here's the cool part: because the photonic crystal can control the way light moves, it can do some really useful things. For example, we have special kinds of photonic crystals that can reflect light of certain colors while letting other colors through. This is how some of our fancy soap bubbles get their color!

We can also use photonic crystals to create special kinds of light sources or sensors. They're like tiny little machines that work with light instead of electricity. Pretty neat, right?