Determination of the dispersion of the phase response of rhodamine 6G and DODCI dyes

An experimental investigation was made of the dispersion of the phase response (i.e., of the frequency dependence of the change in the refractive index caused by illumination with strong light) of solutions of rhodamine 6G and 3,3-diethyloxadicarbocyanine iodide (DODCI) in the spectral range covering the absorption and fluorescence bands. The qualitative nature of the dispersion of the phase response was the same for both dyes and it was in good agreement with the expected behavior.