The absorptances of 633-nm photons by silver island films formed on room temperature substrates were measured in an attenuated-total-reflection geometry by the photoacoustic method as a function of the angle of photon incidence. From the data obtained for s-polarized light ε″, the effective dielectric function for the direction parallel to the film and dopt, the effective optical thickness, were determined as a function of the mass thickness dm of the island films between 2 and 18 nm. The values of ε″ and dopt were then used to calculate the absorptance for p-polarized light assuming that the films were optically isotropic. It was found that the calculated values agreed well with the experimental values indicating that the films were isotropic. The values of dopt agreed well with earlier results from an ellipsometric study in which the films were assumed to be isotropic.
© 1986 Optical Society of America
T. Inagaki, J. P. Goudonnet, P. Royer, and E. T. Arakawa, "Optical properties of silver island films in the attenuated-total-reflection geometry," Appl. Opt. 25, 3635-3639 (1986)