The wavelength of a single mode helium-neon laser, stabilized by saturated absorption in iodine-127 at 612-nm, has been measured on the Michelson interferometer at BIPM. The laser was locked to the i component of the 9-2 R47 iodine line and the measured value of the wavelength was 611970458.6 fm.
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Bennett et al. (1979) studied this question.
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