Measurements of dispersion properties of refractive indices and absorption coefficients in organic-dye-doped thin films by a prism-coupling method

Refractive indices and thicknesses of organic-dye-doped thin films are measured by a prism-coupling method. Anomalous dispersion of refractive indices which is caused by absorption of dyes, can be observed. The measured film thicknesses are used to determine the absorption coefficients of those films together with transmission measurements. In a highly absorptive wavelength region, the accuracy of measurements is decreased as a consequence of the broadening of m line corresponding to each guided mode. From the measurements in eosin-Y-doped polymer films, it is found that this method is not available when transmission is less than about 80%. (C) 1996 Society of Photo-Optical Instrumentation Engineers.