How Laser Can be a Powerful Cutting Tool

We all must have wondered how a simple light called laser can cut through even a powerful metal like steel. This is the explanation that I hope you could understand easily :

Laser device contains a long crystal made of ruby (shown here as a red bar) with a flash tube (yellow zig-zag lines) wrapped around it. The flash tube looks a bit like a fluorescent strip light, only it's coiled around the ruby crystal and it flashes every so often like a camera's flash gun.

So, how do the flash tube and the crystal make laser light?

1. A high-voltage electric supply makes the tube flash on and off.
2. Every time the tube flashes, it "pumps" energy into the ruby crystal. The flashes it makes inject energy into the crystal in the form of photons.
3. Atoms in the ruby crystal (large green blobs) soak up this energy in a process called absorption. When an atom absorbs a photon of energy, one of its electrons jumps from a low energy level to a higher one. This puts the atom into an excited state, but makes it unstable. Because the excited atom is unstable, the electron can stay in the higher energy level only for a few milliseconds. It falls back to its original level, giving off the energy it absorbed as a new photon of light radiation (small blue blob). This process is called spontaneous emission.
4. The photons that atoms give off zoom up and down inside the ruby crystal, travelling at the speed of light.
5. Every so often, one of these photons hits an already excited atom. When this happens, the excited atom gives off two photons of light instead of one. This is called stimulated emission. Now one photon of light has produced two, so the light has been amplified (increased in strength). In other words, "light amplification" (an increase in the amount of light) has been caused by "stimulated emission of radiation" (hence the name "laser", because that's exactly how a laser works!)
6. A mirror at one end of the laser tube keeps the photons bouncing back and forth inside the crystal.
7. A partial mirror at the other end of the tube bounces some photons back into the crystal but lets some escape.
8. The escaping photons form a very concentrated beam of powerful laser light.

Powerful beam of laser light can cut through metal, cloth or ceramics. It's widely used by factory to increase their production. Laser also used on Medical Research and Military Research. It's said that in the future, laser will dominate the military weapon production.

That's all the explanation of laser. You can search on the Internet for more extensive study about laser.

I hope you like it! Thanks!