Lasers are an important technology in modern life. They are not just the energy beams of science fiction and Saturday morning cartoons. They have many important everyday uses that you may and may not be aware of. For example it is a laser in the cd player or dvd player that allows them to play for favorite album or movie. Lasers also are used industry allowing for high accuracy in drilling and cutting. Lasers are also important for guidance systems and measurements due to their high precision. However few people really think about what caused the advent of the laser and even more how lasers work.
The first step to understanding how lasers work is to know where the word laser comes from. Laser is actually an anagram meaning Light Amplified by Stimulated Emission of Radiation. So at the basic level lasers are amplified light. Additional energy is added to laser until its significantly amplified. The way this works is through Einstein’s photoelectric effect. Einstein is considered one of the main pioneers modern research concerning light. He was the first person to conclusively predict that light had a fundamental particle that is called the photon. When the photon hits matter it knocks off an electron from the outermost shell and an additional photon. This principle is used to amplify light so it can become a laser. Next lets see how a laser applies this theory.
A laser consists of a light source, a gain medium, a pump. The reason why laser light is so focused is that is has a property called coherency. This simply means that lasers are highly organized on the quantum level. Each photon is emitted after the other in an orderly fashion. This is something that usually doesn’t happen with light sources. Most light sources from the sun to the flashlight you use in an emergency randomly emit photons. There is very little organization beyond the uniform speed of light. A uniform medium is used so that when excited by a source of electricity the photons will be emitted in order. The light is then bounced back and forth between to highly reflective semi-transparent mirrors to help further amplify the light.
Lasers are an excellent example of the application of quantum physics. Lasers have strong organization over long periods and have wide applications. Some new possible directions that lasers might go are mindblowing in their scope. For example there is the possiblity of the laser processors that would be several times more powerful than current processors on the market. There is also the chance of using lasers to transmit solar energy from satellites to Earth with the potential of powering the entire planet on solar radiation.
We have written many articles about laser for Universe Today. Here’s an article about finding exoplanets using laser combs, and here’s an article about a laser powered plane.
If you’d like more info on laser, check out an article from How Stuffs Work. Also, here’s another article about what is laser from NASA Space Place.
We’ve also recorded an entire episode of Astronomy Cast all Fusion. Listen here, Episode 205: Fusion.
Source:
How Stuff Works
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