Refractive index measurement of optical thin-film

摘要

Method and apparatus for determining the refractive index of an optical film over a wide spectral range is described that involves measuring the changing radiant reflectance (or transmittance) of the film at various wavelengths as it is being deposited upon a substrate, as for example by vacuum deposition process. By determining the values of the extreme limits, an envelope of the peak reflectance can be developed from which the film's index of refraction is obtained over the entire spectral range that is situated between the two extreme wavelength channels.