Fit of Edlen formulae to measure values of the refractive index of air

摘要

Abstract: For accurate interferometric length measurements, the accurately determined value of the refractive index of air is required. In many cases the refractive index is evaluated from measured air parameters. A widely applied set of formulae for this evaluation has been provided by Edlen who fitted existing experimental data. Modified Edlen's formulae are presented which were fitted to values obtained by an air refractometer situated in an environmental chamber. This chamber allows stabilization of the air parameters. A new series of measurements has been performed with three laser wavelengths at 543 nm, 633 nm, and 780 nm and good agreement with the results previously reported has been obtained. !9