yang_2018 ========= L\. Yang, Y\. Li, and H\. Wei, Sci\. Rep\. 8, 16447 \(2018\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1038/s41598\-018\-34641\-y `__ **Source kind:** measurement **Recorded technique:** Absolute group\-refractivity measurement by comb\-mode\-resolved spectral interferometry\: an Er fibre frequency comb \(250 MHz, filtered to 5 GHz mode spacing by a fibre Fabry\-Perot cavity, centre 1530\.8 nm, 37\.5 nm bandwidth\) through a Jamin interferometer with a 396\.000 mm double\-spaced vacuum cell; the comb modes resolved by a VIPA and grating spectrometer on an InGaAs camera; the group refractivity N \- 1 from the FFT of the spectral interferogram \(Eq\. \(6\)\), one measurement in 10 ms \(pp\. 2\-4\)\. **Materials in structured entries:** None recorded. **Dataset quantities:** None recorded. **Contents:** 0 datasets; 0 formulas. Curation notes -------------- No datasets\: the only gas measured is ambient laboratory air \(skipped\: not a curated species\), a 10\-hour record of its group refractive index compared with Ciddor's equation, shown in figures only \(Figs\. 3, 4\)\. The stated combined standard uncertainty is \(N \- 1\) x 4\.7 x 10^\-6, 1\.3 x 10^\-9 for air, dominated by the cell length \(p\. 7\)\. The conclusion \(p\. 7\) proposes measurements of N2, He and CO2 in future work; none are reported\. **Recorded bibliographic identity status:** VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- No datasets are recorded. Formulas -------- No formulas are recorded. Corrections ----------- No dataset errata are recorded in this source record. Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register ` for the checks and decisions.