V-block refractometer for monitoring the production of optical glasses

Highly chromatic corrected optical systems rely on optical glasses with precise optical positions represented by refractive index and Abbe number. A modern production of optical glasses requires an economical, fast and accurate way of monitoring its fabrication. We demonstrate that an automated Hilger-Chance type refractometer fulfills all these needs. Therefore the uncertainty of a set of optical glasses is analyzed on the basis of a high number and long time reproducibility measurements. It turns out that the standard deviations after several hundreds of measurements taken over almost an decade in refraction is better than 10-5 in refraction and 0.02% in dispersion.