Near orthogonal launch of SPR modes in Au films

We report the excitation of a surface plasmon resonance (SPR) close to the orthogonal axis of a gold (Au) film on borosilicate glass. Direct spectroscopic measurement of SPR shifts using different liquids are made at ~5{\deg} incidence within a reflection spectrophotometer. Scattering of light that is able to penetrate across the film at the interfaces is the proposed mechanism by which coupling, and plasmon localization, is established.