HOW HIGH-POWER LASERS WORK
At its most basic level, a laser is a supercharged beam of light particles called photons. The key to getting these particles to do what you want is by ‘exciting’ the photons, which means giving them lots of energy so that they gain enough power to be aimed and fired at a target.
Laser itself stands for ‘light amplification by stimulated emission of radiation’ and consists of four basic parts. The first is a source of atoms in what is called a ‘lasing medium’ – it can be a gas, solid or liquid. The second is an energy source, which is needed to get the atoms ‘excited’. The third is mirrors, usually a full mirror and a half-silvered mirror. These are used to allow the emitted light to bounce back and forth in the lasing medium while they build up energy. The fourth component is a lens, which focuses the beam of now-excited photons and allows it to be aimed at a target.