Development of a New Interferometric Measurement System for Determining the Main Characteristics of Gauge Blocks

“…The typical method to mount the sample is to wring it to a reference flat, which has been shown to contribute considerable measurement uncertainty [4,5]. This is a particular problem for single-sided instruments by, for example, Bennett [6], Birch [7], Okaji and Imai [8], and Schödel [5].…”

Section: Instrument Specificationmentioning

confidence: 99%

“…Several doublesided instruments have been developed that alleviate this problem; however, these still have additional problems that need to be resolved. These include a contact-based measurement causing additional instability [9]; a secondary reference, which allows only relative measurements [10]; and a wide diameter beam, which will be more subject to refractive index changes [4]. This research will focus on designing an instrument that is not subject to the aforementioned additional uncertainty contributors [11].…”

Section: Instrument Specificationmentioning

confidence: 99%

Balanced interferometric system for stability measurements

et al. 2009

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We describe two different, double-sided interferometer designs for measuring material stability. Both designs are balanced interferometers where the only optical path difference is the sample and the reference beams are located within the interferometer. One interferometer is a double-pass design, whereas the other is a single-pass system. Based on a tolerancing analysis, the single-pass system is less susceptible to initial component misalignment and motions during experiments. This single-pass interferometer was tested with an 86 nm thin-film silver sample for both short-term repeatability and long-term stability. In 66 repeatability tests of 30 min each, the mean measured drift rate was less than 1 pm=h rms. In two long-term tests (>9 h), the mean drift rate was less than 1:1 pm=h, which shows good agreement between the short-and long-term measurements. In these experiments, the mean measured length change was 2 nm rms.

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“…Repeated wringing of gauge blocks causes wear of both the block and the platen, so several non-contact measurement methods, using double-ended interferometry, have been developed [3][4][5][6][7][8][9][10]; here the correction becomes even more Metrologia Linking the optical and the mechanical measurements of dimension by a Newton's rings method important as it has to be applied twice (once at each end). One of these methods-Fourier transform interferometry [9]-is regularly used in the Czech Metrology Institute (CMI) to calibrate both short and long gauge blocks because it is competitive with comparator measurements while achieving precision comparable to standard interferometric methods.…”

Section: Introductionmentioning

confidence: 99%

Linking the optical and the mechanical measurements of dimension by a Newton’s rings method

et al. 2019

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Optical (e.g. interferometric or laser focus probe) measurement of dimensions must be corrected to take into account phase change on reflection and the influence of surface roughness in order to be compatible with mechanical dimension measurement methods (e.g. tactile probes). One typical example is interferometric measurement of a gauge block; while a correction of only a few nanometres is needed for standard interferometric measurement of a gauge block wrung on a platen made of the same material, a correction of tens of nanometres is needed when different materials are used (e.g. a steel gauge block on a glass platen) and even a total correction of up to a hundred nanometres is needed for some gauges when a double-ended interferometer is used. Here we describe and evaluate a Newton's rings method that enables direct estimation of such correction. The implementation of this method is described, the sensitivities to experimental adjustments are discussed, and the results are compared with standard measurements within EURAMET project No. 1272. The resulting central length measured with a double-ended interferometer and corrected using the Newton's rings method agrees well with the standard measurement results within a total uncertainty of ±20 nm for both steel and ceramic gauges. Unlike the stack method, the Newton's rings method enables measurement of the correction for an individual sample (e.g. gauge block) and can easily be done for both short and long gauges with equal speed and uncertainty.

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Development of a New Interferometric Measurement System for Determining the Main Characteristics of Gauge Blocks

Cited by 21 publications

References 4 publications

Length Traceability Using Interferometry

Length Traceability Using Interferometry

Balanced interferometric system for stability measurements

Linking the optical and the mechanical measurements of dimension by a Newton’s rings method

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