Practical realization of the definition of the metre, including recommended radiations of other optical frequency standards (2001)

In 1983, at the time of the adoption of the present definition of the metre by the 17th General Conference on Weights and Measures (CGPM), the International Committee for Weights and Measures (CIPM) drew up recommendations for the practical realization of the definition. These have formerly been referred to as the mise en pratique of the definition of the metre. It was understood that the practical realization would, from time to time, be updated to take account of new measurements and improvements in techniques of laser stabilization. In 1992 the CIPM, acting on the advice of the then Consultative Committee for the Definition of the Metre (CCDM), adopted a revision of the mise en pratique in its Recommendation 3 (CI-1992). The text was published in Metrologia (1993/94 30 523–41). In 1997 a second revised version of the practical realization of the definition of the metre was adopted by the CIPM in its Recommendation 1 (CI-1997). The text was published in Metrologia (1999 36 211–44). In 2001, the CIPM again adopted a revised version of the practical realization of the metre and this time included recommended frequencies for other optical frequency standards. The text of this Recommendation (Recommendation 1 (CI-2002)) is given here∗. In addition, a revised list of recommended radiations, and an appendix containing the source data used in estimating the wavelengths, frequencies and uncertainties of the recommended radiations are given. In adopting the revised practical realization, the CIPM acknowledged the considerable effort put into its preparation by the Consultative Committee for Length (CCL) through its Working Group on the mise en