Absolute frequency measurements of stabilized lasers (MeP) in northern Europe for BIPM.L-K11

Project Description

A key comparison BIPM.L-K11 is ongoing to achieve traceability for primary wavelength standards at wavelengths in the list of recommended radiations that are used in dimensional metrology. In order to claim traceability in compliance with the MRA and related ISO/IEC 17025, comparisons of primary standards are needed when realizing the definition of the SI-metre according to the method (c) in the Mise en Pratique (MeP) and a traceable link to the SI-second using calibrated instruments and validated measurement techniques in the case of method (b). In the K11, in addition to measurements carried out at the BIPM, absolute frequency determinations are expected to be made in regional comparisons, also.

MIKES offers to act as a regional host in northern Europe for the BIPM ongoing key comparison on primary wavelength standards (BIPM.L-K11). MIKES provides absolute frequency measurements of lasers stabilized to iodine according to the international recommendations at wavelengths 633 nm and 532 nm (and possibly in the near future at 543 nm and 612 nm, also). The absolute frequency measurements are carried out according to the technical protocol for the K11: either by the MIKES frequency comb or by a MIKES primary wavelength standard, whose absolute frequency is determined by a comb. The MIKES frequency comb generator is traceable to the SI-second via an active hydrogen maser and a Cs-atomic clock and it is validated by absolute frequency measurements of our 633-nm and 532-nm primary wavelength standards, whose absolute frequencies have also been determined at BIPM.

Final Report 2007-02-05

The purpose of the project was the following: MIKES offered to act as a regional host in northern Europe for the BIPM ongoing key comparison on primary wavelength standards (BIPM.L-K11).
As the BIPM key comparison is closed and as the CCL has taken the responsibility of organizing a key comparison for primary wavelength standards (CCL-K11), it was agreed in the first meeting of Euramet Technical Committee for Length (29–30 October 2007, Malta):

• to close the project 873, which concerned lasers within northern Europe
• to start a new project which will cover all of the EURAMET NMIs and whose purpose is to
  yearly report on any work performed in Europe under the CCL key comparison for primary wavelength standards
   

Hence, the project 873 will be declared as finished.