title: Toward subnanometer uncertainty in interferometric length measurements of short gauge blocks.
abstract: A primary-level comparator, with a reproducibility of 0.2 nm and intended for realization of a Systeme International length unit in the range of 1-100 mm, is reported. High-precision differential measurements of phase change on reflection from blocks and end plates are demonstrated. A set of experiments has been developed to measure systematic error associated with nonideal interferometer optics and deviations from flatness of an auxiliary plate. For specially selected high-grade 6-mm blocks, reproducible wringing has been achieved with a random uncertainty in length measurements of 0.1-0.2 nm. Subnanometer wear-off of the blocks as a result of the cleaning has been detected. Under the conditions of reproducible wringing, the accuracy of the length measurements is evaluated to be in the 2-3-nm range for 6-mm blocks.
authors.affiliation: Diretoria de Metrologia Científica e Industrial, Divisão de Optica, National Metrology Institute, Avenada Nossa Senhora das Graças 50 Xerém 25250-020 Duque de Caxias, Rio de Janeiro, Brazil. igor.malinovsky@usa.net
authors.forename: I
authors.initials: I
authors.lastname: Malinovsky
authors.forename: A
authors.initials: A
authors.lastname: Titov
authors.forename: J A
authors.initials: JA
authors.lastname: Dutra
authors.forename: H
authors.initials: H
authors.lastname: Belaïdi
authors.forename: R dos S
authors.initials: Rdos S
authors.lastname: França
authors.forename: C A
authors.initials: CA
authors.lastname: Massone