This paper reports the third set of results of a series of grouped laser comparisons from national laboratories undertaken by the Bureau International des Poids et Mesures (BIPM) at the request of the Comité Consultatif pour la Définition du Mètre (CCDM) for the period July 1993 to September 1995. The results of this comparison, involving eight lasers, are comparable with those obtained during a first comparison in 1988 involving most of the same national laboratories. The lasers were first compared with the BIPM lasers with the parameters set to the values normally used in each laboratory, the results then ranged from -23 kHz to +28.2 kHz. After checking and readjusting the values of all the parameters, the range was reduced to -20.4 kHz to +9.7 kHz. Under the latter conditions, the average frequency difference of the group of lasers, with respect to the BIPM4 laser, was -5.8 kHz with a standard uncertainty of 12.3 kHz. Typical frequency stabilities with Allan standard deviations of about 1.8 10 -11 and 1.8 10 -12 were observed with sampling times of 1 s and 100 s, respectively.
The comparison of two lasers from the Slovak Institute of Metrology (SMU, Slovakia) and one laser from the Bundesamt für Eich-und Vermessungswesen (BEV, Austria) in March 2000 followed that undertaken by the Bureau International des Poids et Mesures (BIPM) at the BEV in September 1999. These two comparisons were indirectly linked through the frequency of the BEV2 laser. As a first step, two SMU lasers (SMU-B2 and SMU-B3) were compared with BEV2 (in this case the reference laser) and then the SMU lasers were mutually compared, with the parameters of all three lasers set up as they are normally used. Uncorrected frequency differences with respect to BEV2 were -15.2 kHz (SMU-B2) and +19.7 kHz (SMU-B3), i.e. within the expanded uncertainty of 2 24 kHz (5 10 -11 ) recommended by the International Committee for Weights and Measures (CIPM). Taking into account the correction to the recommended values of the parameters, these differences were reduced to -5.1 kHz and +4.6 kHz, respectively. After transfer to the BIPM reference laser, the differences of the SMU lasers were -7.4 kHz and +2.3 kHz, respectively, i.e. within the range of 1 12 kHz (2.5 10 -11 ) recommended by the CIPM for laser parameters meeting the recommended values. The best frequency stabilities, expressed as relative Allan standard deviations, were 8.0 10 -12 , 2.6 10 -12 and 9.2 10 -13 for sampling times of 10 s, 100 s and 1000 s, respectively. The overall best value was 6.0 10 -13 for a sampling time of 2500 s.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.