What Is a Laser?

The word "laser" is an acronym, a word formed from the first letters of a series of words. "Laser" actually stands for "light amplification by stimulated emission of radiation."

Invented in the 1950s, the laser is the most powerful source of energy man has discovered. To create a laser beam, light is focused on a ruby crystal that is kept very cold.

The light stimulates certain atoms in the ruby, which emit a very powerful red light. This light can be focused into a beam so strong that it can burn a hole in a diamond in just 1/5000 of a second!

A laser beam emits more energy per square inch than the sun — about 2,000 times as much!