But what is a laser? How is laser light different from regular light?
You can figure this out by playing with different kinds of light in the demonstration
below. Notice how the distance between peaks, the "wavelength", changes with the color.
With laser light all the crests and troughs line up with each other.
Yes that means that all the light is exactly the same color. We call that "monochromatic".
But the laser light has a second thing that is special. All the waves are going in the
same direction. It is much more "orderly" than the other light.
That is exactly what makes laser light special. It is very organized waves with all the
light exactly the same color and going in exactly the same direction. We can also think of
light as little particles. With a laser these particles come in a perfectly uniform stream
all going in the same direction. Because it is so orderly we can control laser light
extremely well, and that is why we can use it to do so many things.
Cool. But now I want to find out how we produce light like that...