The effect of surface plasmon generation on the reflectivity of thin metal films in attenuated-total-reflection prism configurations has been described as a means of determining the film dielectric function and thickness. Although this technique is capable of yielding accurate values for the film parameters with relatively simple equipment, there is an ambiguity in fitting to the measured reflectivity data. Previous research had shown that the ambiguity could be removed by further reflectivity measurements with different conditions; however, we find that this is not necessarily true. We describe the conditions under which a unique determination of the film parameters is ensured and demonstrate that even with ambiguous results the true solution can usually be determined by a supplementary optical measurement.
© 1989 Optical Society of America
W. M. Robertson and E. Fullerton, "Reexamination of the surface-plasma-wave technique for determining the dielectric constant and thickness of metal films," J. Opt. Soc. Am. B 6, 1584-1589 (1989)