Reported April 2009

HOW LASERS WORK: "Laser" is an acronym for Light Amplification by Stimulated Emission of Radiation. It describes any device that creates and amplifies a narrow, focused beam of light whose photons are all traveling in the same direction, rather than emitting every which way at once. Lasers can be configured to emit many different colors in the spectrum, but each laser can emit only a single color. There are many different types of laser, but all of them have an empty cavity containing a lasing medium: either a crystal like ruby or garnet, or a gas or liquid. There are two mirrors on either end of the cavity, one of which is half-silvered, meaning that it will reflect some light and let some light through. In a laser, the atoms or molecules of the lasing medium are "pumped" by applying intense flashes of light or electricity. The end result is a sudden burst of so-called "coherent" light as all the atoms discharge in a rapid chain reaction.

ABOUT COMPUTER MODELING: PComputer modeling is used to simulate the structure and appearance both of static objects, such as building architecture, and of dynamic situations, such as a football game. Computer models can enable the user to test the consequences of choices and decisions. They can provide cutaway views that let you see aspects of an object that would be invisible in the real artifact, as well as visualization tools that can provide many different perspectives. Physical models that reproduce behavior are limited by the physics of the world, while computer models have much looser bounds. Physical models of living things can reproduce very few behaviors compared to simulation models, and physical models simply cannot capture the sorts of species-level and conceptual-level phenomena that artificial life and artificial intelligence models do. Computer models enable you to run companies and civilizations, fight battles, play football games and evolve new species.

The Human Factors and Ergonomics Society and the Institute of Electrical and Electronics Engineers, Inc.-USA contributed to the information contained in the TV portion of this report.

If you would like more information, please contact:

Richard Lewis
Public Affairs
(401) 863-3766
Richard_Lewis@brown.edu

Lois Smith
Human Factors and Ergonomics Society
Santa Monica, CA 90406
(310) 394-1811
http://www.hfes.org
lois@hfes.org

Institute of Electrical and Electronics Engineers, Inc.
IEEE
IEEE-USA:
Pender McCarter
http://www.ieee.org
http://www.ieeeusa.org

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