National Institute of Advanced Industrial Science and Technology (AIST) This page is a page of the former research institute. We stopped updating on March 31.2001.
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Length Standard

The meter is the unit of length determined by the speed of light in a vacuum.


Evolution of the length standaed.
International Comparison of Wavelength and Optical Frequency

The wide applicability of length standard is being internationally endorsed. The NRLM and the International Bureau of Weights and Measures are corroborating on the comparison of the iodine-stabilized He-Ne laser and the methane-stabilized He-Ne laser, and the adjustment of the length standard from 10-10 to a greater accuracy.


Iodine-stabilized He|Ne laser at 633 nm.


International interomparison of iodine stabilized He|Ne lazers.



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