We propose a new procedure for evaluating the complex refractive index
of a metal film, based on transmission measurements at different inci
dence angles. The method is simpler and faster than standard ellipsome
try and performs the accuracy required for the design of fiber-optic a
ttenuators for telecommunications. As an example, we report on a devic
e showing a constant attenuation on the 1200-1600-nm wavelength range.
(C) 1998 Optical Society of America.