Friday, October 9, 2009

How Do Lasers Work

Atoms and Energy


To understand how a laser operates, it's important to know the basics behind the atom, the principle part of everything in the world, whether it is a gas, liquid or solid. Atoms are formed by a nucleus in the center made of tightly packed protons and neutrons and a cloud of electrons in various states that move in different paths around the nucleus. Electrons each carry different amounts of energy; an electron is said to be more excited when it has more energy and therefore travels in a wider arc, farther away from the nucleus. However, electrons want to be closer to the nucleus and they will release energy in order to fall in closer and form a tighter orbit. When they release this energy, they do so in the form of photons, which are light particles. These photons can be different colors and wavelengths, depending on the type of lasing material they are part of. It is this simple process that is the basis for understanding how lasers work.


Makeup of a Laser


A laser consists of few components, making it a surprisingly simple contraption. Basically, it consists of a long tube that houses the lasing material. There are many different types of these that can be used, and each will create a different type of laser. Some examples of lasing materials: rubies, helium, carbon dioxide, krypton, xenon, rhodamine 6G, or a semiconductor. This material remains in the tube until it is excited. On either end of the tube are two mirrors, one of which has a small hole or slit in it used to concentrate the laser. Over the tube is a flash tube that emits light in high volumes and density.


How a Laser is Created


When the flash tube is turned on, it emits photons and sends them into the lasing material. These photons give energy to the electrons in the atoms inside and excites them. The electrons, in turn, release more photons as they change orbital paths. Photons start to move throughout the tube, bouncing off the mirrors at either end and exciting more electrons as the move. A large amount of photon energy becomes present very quickly as more and more electrons are excited and release energy of their own, which excites the electron nearby. This continues to happen as long as energy is being pumped into the lasing material. Since one mirror in the tube has a small slit, energy passes through it in a concentrated form, which happens to be the laser itself.

Tags: lasing material, flash tube, into lasing, into lasing material, more electrons