A Brief History of Time Nobel Prizewinner Bill Phillips (#265)
Into the Impossible With Brian Keating
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The Iodine Stabilized Helium Neon Laser
In 1960, which was the year the laser was invented, they defined the light from this lamp. By 1983, people had decided we have to redefine the meter because it's defined in terms of this crummy, now crummy, Krypton lamp compared to this beautiful laser. The obvious thing to do would have been to define the meter in terms of the wavelength of the iodine stabilized helium neon laser. Fortunately, they did not make the obvious choice. Instead, they made a brilliant choice. They defined the speed of light. Why does that work? Because of this universal relationship, the wavelength of light times its frequency is equal to the speed oflight regardless of what the wavelength is.
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