Laser

The Laser

Definition :

The term “Laser” means Light Amplification by the Stimulated Emission of Radiation. This device creates a uniform and coherent light (different from an ordinary light bulb).

The process is based on an optical amplification, by stimulating the emission of photons.

Many lasers are able to deliver a light where the beam is parallel and approaching a single wavelength and thus very pure.

Schematic:

How it work ?

A laser is an optical oscillator, which is can be made out of a solid, liquid or gas. It contains two with mirrors at both ends: one is totally reflecting and the other only partially. To make it work, the material is excited or "pumped," with an energy source such as light or electricity.

When this energy source gives energy the electrons in the atoms, they become excited. But the interesting part is when a few of the electrons drop back to lower energy levels spontaneously, and then release a photon (or a quantum of light). The photons created stimulate other excited electrons and emit more and more photons. Then the light waves (photons), which passes through the laser medium, is reflected by the mirrors at both ends. It keeps the light back and forth creating a chain reaction. After that, the light beam goes out through the output.

Uses of Laser:

Gas Lasers

A specific type of laser is the gas laser. There are many types of gas lasers, as each one uses a specific type of gas to create the laser emission. For example, a helium-neon laser uses HeNe to produce varied wavelengths. Because of the flexibility of this laser light, it can be created through a low budget, making it especially useful in education institutions and other organizations with limited funding.

Chemical Lasers

Another type of laser is a chemical laser, which is created through artificially induced chemical reactions. These chemical lasers are capable of high energy outputs and deliver consistent emissions, making them very useful for machines and equipment that require continuous operation.

Excimer Lasers

Excimer lasers also call on the power of chemical reactions. Although not in every single case, they usually tend to create ultraviolet light and are used in semiconductor photolithography and in LASIK eye surgery. LASIK eye surgery has become a commonplace procedure, allowing patients to receive treatment and return home the same day.

Solid State Lasers

Solid-state lasers are among the most useful lasers that exist today, finding applications in a number of different arenas. This laser technology is used on a daily basis, including materials processing, such as welding and cutting. Solid-state lasers are also used in semiconductor fabrication, graphic arts and medical and surgical operations and procedures.

Pointers

Laser lights are also used as simple, harmless laser pointers for school and office presentations. These handy devices help people point to exact locations on slides, helping them deliver smooth-flowing, precise presentations. Some are even used in cat toys as the animals enjoy chasing the beam up the wall.

Entertainment

Another popular use of laser lights is for entertainment purposes, such as light shows at theme parks, special effects in movies and stage effects for concerts.

Applications of Laser :

The laser is part of our daily life. Many examples…

The laser pointer used in classrooms	The CD in a computer or in a hi-fi that are used to read the data stored in a CD.
In industry, laser is often used for cutting and microscopic processing.	For military purposes, laser is used to intercept guided missiles.
Lasers are used to measure distance.