Optical constants measurements of strongly absorbing media.

An experimental arrangement is described for determination of refractive indices n and extinction coefficients k of strongly absorbing liquids and solids over a wide spectral region. The reflectivity of parallel polarized light vs angle of incidence is measured, and the optical constants are calculated from the minimum parallel reflectivity and the corresponding Brewster angle. The accuracy of n and k determination is analyzed. The refractive indices and extinction coefficients of 0.4-M rhodamine 6G in methanol are presented around the St absorption band.