How was the laser discovered?

Omar Gamel
23 January 2012

The word laser is actually an acronym that stands for light amplification by stimulated emission of radiation. As we all know, a laser is a concentrated beam of light, but how is it different from the light that comes from a regular incandescent light bulb?

The main difference is that it is "coherent," whereas regular light is "incoherent." This means the little "bits" of regular light (called photons) move without a specific pattern, like a large angry mob. Laser light is more like a marching army band, where all individuals, wearing the same colour move together in unison, in the same direction, with an identical pattern.

Did You Know?
because lasers don't spread out much, they are excellent for sending signals over long distances. Think of a laser pointer versus a flashlight, which one travels further?

Einstein was one of the first to think about the science behind lasers, publishing a paper about "the quantum theory of radiation" in 1917. He reasoned that you can "excite" a whole bunch of atoms by giving them some energy, and then have them all release it in a unified beam of light at the same time. This is the "stimulated emission of radiation" part. It took a few decades of scientists’ hard at work until Charles Townes came up with the "maser" in 1954. This is the laser's older and less famous cousin, where "microwaves" are used instead of light. And yes, these are the same kind of microwaves that make it possible for you to warm up food.

Did You Know?
microwaves, visible light, x-rays, and gamma rays are all examples of electromagnetic radiation. The ones we cannot see, like microwaves, are sometime called invisible light.

By 1960 the first laser was devolved using visible light. Today, lasers are used in everything from superfast data transfer to entertaining laser shows in events and celebrations.

Did You Know?
Laser beams concentrate a large amount of power in small area, making them excellent alternatives to scalpels in surgery.

Learn more!

History of Lasers

Wikipedia: Laser

How Lasers Work

Article first published May 11, 2011

Omar Gamel

I am a PhD student studying Physics @ the University of Toronto. I study Quantum Optics, and love all things quantum. I enjoy teaching science, and have a great interest in education. In my spare time, I am an avid reader, and volunteer in various organizations. I also learned to juggle, in case physics doesn't work out.


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