We present a method of measuring the refractive index of dry gases absolutely at 632.8 nm wavelength using a Fabry-Perot cavity with an expanded uncertainty of <3×10⁻⁹ (coverage factor k=2). The main contribution to this uncertainty is how well vacuum-to-atmosphere compression effects (physical length variation) in the cavities can be corrected. This paper describes the technique and reports reference values for the refractive indices of nitrogen and argon gases at 100 kPa and 20 °C with an expanded uncertainty of <9×10⁻⁹ (coverage factor k=2), with the additional and larger part of this uncertainty coming from the pressure and temperature measurement.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1364/AO.50.003076 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Convolutional neural network-based regression analysis to predict subnuclear chromatin organization from two-dimensional optical scattering signals.
J Biomed Opt
August 2024
Middle East Technical University, Northern Cyprus Campus, Physics Group, Kalkanli, Turkey.
Significance: Azimuth-resolved optical scattering signals obtained from cell nuclei are sensitive to changes in their internal refractive index profile. These two-dimensional signals can therefore offer significant insights into chromatin organization.
Aim: We aim to determine whether two-dimensional scattering signals can be used in an inverse scheme to extract the spatial correlation length and extent of subnuclear refractive index fluctuations to provide quantitative information on chromatin distribution.
We propose a new, to the best of our knowledge, rainbow technique called three-dimensional rainbow refractometry (TDRR), with a cylindrical lens in the signal collecting system. With a TDRR model based on the ray transfer matrix developed, it is proved that the tilt angle of the rainbow signal is related to the axial position of the droplet, which helps to obtain the 3D position. By converting rainbow scattering angle calibration into the system parameter calibration, a new rainbow data processing program is written in combination with the model to obtain the refractive index and the particle size.
View Article and Find Full Text PDFTwo-Dimensional SEC-SEC-UV-MALS-dRI Workflow for Streamlined Analysis and Characterization of Biopharmaceuticals.
Anal Chem
March 2024
Analytical Research and Development, MRL, Merck & Co., Inc., 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States.
The emergence of complex biological modalities in the biopharmaceutical industry entails a significant expansion of the current analytical toolbox to address the need to deploy meaningful and reliable assays at an unprecedented pace. Size exclusion chromatography (SEC) is an industry standard technique for protein separation and analysis. Some constraints of traditional SEC stem from its restricted ability to resolve complex mixtures and notoriously long run times while also requiring multiple offline separation conditions on different pore size columns to cover a wider molecular size distribution.
View Article and Find Full Text PDFImproved filters for angular filter refractometry.
Rev Sci Instrum
February 2024
University of Rochester Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623-1299, USA.
Angular filter refractometry is an optical diagnostic that measures the absolute contours of a line-integrated density gradient by placing a filter with alternating opaque and transparent zones in the focal plane of a probe beam, which produce corresponding alternating light and dark regions in the image plane. Identifying transitions between these regions with specific zones on the angular filter (AF) allows the line-integrated density to be determined, but the sign of the density gradient at each transition is degenerate and must be broken using other information about the object plasma. Additional features from diffraction in the filter plane often complicate data analysis.
View Article and Find Full Text PDFArticle Synopsis
- The study analyzed discrepancies in fatty acid compositions measured by gas chromatography (GC) and near-infrared fiber-optic method (NIR) in bovine fat, focusing on refractive index values.
- Using intermuscular fat from 45 crossbreeds, the researchers found that both SFA and MUFA measurements had strong correlations (≥ 0.8) between GC and NIR and with refractive index.
- The findings suggested that measurement errors lead to significant differences (over 3%) between GC and NIR, and reanalyzing GC samples using refractive index could enhance accuracy by slightly reducing these discrepancies.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!