TITLE:
Is the Two-Color Method Superior to Empirical Equations in Refractive Index Compensation?
AUTHORS:
Dong Wei, Kiyoshi Takamasu, Hirokazu Matsumoto
KEYWORDS:
Two-Color Method, Length Measurement, Sensitivity Coefficient, Uncertainty, Empirical Equations
JOURNAL NAME:
Optics and Photonics Journal,
Vol.6 No.8B,
August
25,
2016
ABSTRACT: The Edlén empirical equations and the two-color method are the commonly used approaches to converting a length measured in air to the corresponding length in vacuum to eliminate the influence of the refractive index of air. However, it is not well known whether the two-color method is superior to empirical equations in refractive index compensation. We investigated the uncertainties of these approaches via numerical calculations of their sensitivity coefficients of environmental parameters. On the basis of a comparison of their uncertainties, we found that in a 0% humidity environment, the two-color method had potential to provide greater measurement accuracy than the empirical equations.