Bt. Hallam et al., Ultraviolet surface plasmons on aluminium and a non-contact technique for characterizing short-pitch gratings, J MOD OPT, 46(7), 1999, pp. 1099-1105
In this work we present grating-coupled surface plasmon characterization of
aluminium in the ultraviolet. Light of wavelength 325 nm from a helium-cad
mium laser was used to excite surface plasmon-polaritons both at a buried a
luminium-silica interface and on oxidized aluminium. By fitting the angle-d
ependent reflectivity data to model grating theory, the optical permittivit
y of uncontaminated aluminium at 325 nm is deduced. These results are compa
red with those extrapolated from prism-coupled surface plasmon excitation i
n the visible. The further characterization of the oxidized aluminium allow
s optical non-contact profilometry to be performed on short-pitch gratings
that are opaque or are comprised of materials with ill-defined optical prop
erties. This profile characterization is demonstrated for a short-pitch gra
ting manufactured in photoresist.