A laser is an optical amplifier: its fundamental components, a pair of end cavity mirrors and a lasing medium, aim at producing more light than is put in to get it to work! The lasing medium is the heart of a laser: it is the material that emits the light in a laser. The end cavity mirrors reflect that light back and forth so it can pick up more and more power before it gets released into the world as a laser beam.
If you read early science fiction, such as H. G. Wells’ The War of the Worlds, you will see mention of death rays. Although we might describe these weapons as lasers nowadays, Wells would not know what we were talking about. That is because the word laser was only coined in 1959 by Gordon Gould, to stand for “Light Amplification by Stimulated Emission of Radiation”. The first lasers were then developed between 1959 and 1960 in America. As with many other advances in science, the development of the laser is not an island: the theoretical basis for stimulated emission was proven in the early twentieth century by physicists working on quantum mechanics. The laser then grew out of work done in the 1950’s by several scientists including Gould, as well as Charles H. Townes on stimulated emission of microwaves, a MASER.
Since then, the laser has undergone through many, many innovations. Modern lasers can be continuous wave, like a laser pointer or laser cutter, or pulsed, like the lasers used in industries for welding or cutting. The lasing medium can be gasses, such as a mixture of helium and neon or CO2, or solid, like a Titanium doped Sapphire crystal, and in the past, has even included messy dyes specially designed for the purpose.
Just as there are many different lasers, there are a wide range of applications for these lasers. Some lasers are very high powered and are used to cut or weld car chassis, others are only ever on for a very short amount of time, these pulsed lasers can be used in a wide range of research and industrial applications.
Learn more about the history of the laser at the SPIE’s virtual exhibition. Or check out this article from Photonics Spectra.
To learn more about lasers, visit LaserFest
There are a wide range of research groups all over New Zealand using lasers, if you’d like to find out more, visit the website of your nearest university or tertiary institution and get in touch!
The War of the Worlds book cover design by McJade on Deviant Art. Accessed 2:52pm 10/09/2014
Image of Gordon Gould from wikimedia. Accessed on 2:58pm 10/09/2014.
Mario Bertolotti, History of the Laser, CRC Press, 2004
Melinda Rose, “History of the Laser: A trip through the Light Fantastic”, http://www.photonics.com/Article.aspx?AID=42279, accessed on 15/09/2014
Laser Fest, “About Lasers”, http://laserfest.org/lasers/index.cfm, accessed on 15/09/2014
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