Lasers

Lasers

Lasers have become a very useful invention and have been used in a variety of applications throughout the world, ranging from medical procedures such as laser-eye surgery to simply using a laser to engrave one's initials onto an item of value. The word laser is actually an acronym that stands for light amplification by stimulated emission of radiation, which essentially describes the process by which lasers work.

There are many types of lasers - each with their own distinct features. Often times, the laser is named after the lasing medium that is used. The lasing medium is used to excite the atoms into their excited state; when in their excited state, these atoms release energy in the form of photons, thus creating the laser beam.

Laser Light

Laser light is much different than normal light. Unlike the UV visible spectrum of light where many wavelengths are seen, laser light is monochromatic, meaning when shone, it has one wavelength, resulting in only one color seen. The wavelength depends on the amount of energy released by the electron when it is stimulated.

Another difference between laser light and normal light is its state when shone. Laser light is very directional, which explains why when a laser is shone, the beam is very concentrated and organized - there is no or very little scattering of the light. This feat is extremely helpful when considering the applications such as laser-eye energy where focusing and precise energy is needed.

History

The theory of stimulated emission was first discovered by Albert Einstein in 1917. Stimulated emission describes the process of a incoming photon interacting with an excited electron causing the electron to decrease in energy level. The incoming photon must be equal to the difference in energy between the electron's current level and a lower level - this "stimulate a transition" to the lower energy level resulting in the emission of another photon. [1]. Although Einstein introduced this new concept, scientists such as Charles Townes, Joseph Weber, Alexander Prokhorov and Nikolai G. Basov did notable work to apply this concept of stimulated emission to practical uses. They first started researching into MASER (Microwave Amplification by the Stimulated Emission of Radiation), which was used to amplify microwaves in microwave communication systems. Townes and Prokohorov did significant work with the stimulated emissions, but it wasn't until 1960 that the first Laser was invented by Theodore Maiman.

Types of Lasers

Ruby Lasers

Ruby lasers have a flash tube and two mirrors. In this case, the lasing medium is the ruby rod. When light is flashed, the atoms in the ruby get excited and some of these atoms emit photons, which bounce off the mirrors and are eventually emitted as monochromatic and directional laser.

Solid-state Lasers

In solid-state lasers, the lasing medium is distributed in a solid matrix such as ruby.

Gas Lasers

The Lasing medium in this case is usually either helium or helium-neon. They usually have an output color of red. Carbon dioxide is used as a lasing medium when the lasers are being used to cut hard materials.

Semiconductor Lasers

These are also called diode lasers and are different from solid-state lasers. They are usually very small and use a very small amount of power. These lasers are incorporated into a larger arrays.

Connectedness

Lasers are a very unique invention because they have so many applications, as mentioned before. They can be used as a method to decorate objects and have also been applied to the medical field -laser-eye surgery. The concept and process by which lasers work is directly related to physics, specifically the idea of energy emission in the form of photons. This may not have a direct relationship to chemical engineering, but the basic principles of chemistry - atoms and energy - play a large part in the manufacturing of lasers. Industrial applications range from cameras, firearms, scientific techniques such as spectroscopy, and also daily use during presentations. An interesting recent application of lasers is the laser focus that is implemented in LG G3 phone camera. Click on the link below to read more about this feature.

See also

This link has more information about the laser used in the LG G3 phone camera. [ http://www.trustedreviews.com/opinions/how-the-lg-g3-laser-af-camera-focus-works]

References

This section contains the the references you used while writing this page

1. http://science.howstuffworks.com/laser5.htm
2. http://www.laserfest.org/lasers/images/rubylaser_components.jpg
3. http://hyperphysics.phy-astr.gsu.edu/hbase/mod5.html#c3
4. http://www.worldoflasers.com/laserhistory.htm