NIST physicist Jan Hall measured the wavelength of an iodine-stabilized helium neon laser against the existing length standard—the wavelength of a Krypton discharge lamp—while Evenson and Jennings used their newly developed technology to measure the laser's frequency. The product of these two measurements (wavelength multiplied by frequency) yielded the value for the speed of light that was used for the new definition of the meter.
These three-dimensional measuring systems have become essential for large-scale precision manufacturing, particularly in aerospace, where laser trackers have almost completely replaced traditional techniques for measuring and accurately assembling airplanes.
Laser trackers are also widely used in the automotive, shipbuilding, machine tool, robotic, heavy industry, and energy sectors.'
Phillips and his team made numerous pivotal contributions to laser cooling, including Zeeman slowing of atomic beams, magnetic trapping of laser-cooled atoms, and trapping of atoms in optical lattices. In recognition of this work, Phillips shared the 1997 Nobel Prize in physics with Steven Chu (now U.S. Secretary of Energy) and French physicist Claude Cohen-Tannoudji . http://physics.nist.gov/News/Nobel/1997nobel.html