ELI5: Explain Like I'm 5

free-electron laser

A laser is like a flashlight that makes a very special type of light called coherent light. Coherent light means that all the light is the same size and shape and moves together in the same direction. But there are different types of lasers, and one of them is called a free-electron laser!

A free-electron laser works by using electrons that are moving really fast. These electrons are shot through a series of magnets that make them wiggle back and forth as they move. This wiggling motion makes the electrons give off light that is the same shape and size as the wiggles.

But there's a special part of the free-electron laser that makes it different from other lasers. The electron beam (the bunch of fast-moving electrons) is free, meaning it is not trapped in a solid material like other lasers. This means that the free-electron laser can create light in wavelengths and shapes that other lasers cannot.

Scientists use free-electron lasers to study things that are too small or too fast to observe with regular microscopes or cameras. They can also help make materials that are better at conducting electricity or absorb radiation. It's like using an extra special flashlight to see things that we couldn't see before!