Dispersion of a light-induced change in the refractive index of solutions of rhodamine 6G and DODCI dyes influenced by absorption from an excited singlet state

An experimental investigation was made of the frequency dependences of light-induced changes in the absorption coefficient and in the refractive index of solutions of rhodamine 6G and DODCI dyes in the frequency range covering absorption, fluorescence, and induced absorption bands. The dispersion of the light-induced changes in the refractive index could be calculated from the spectrum of changes of the absorption coefficient by applying the Kramers–Kronig transformation.