In 2001 the American Physical Society published a study on the visualization of the excitation and propagation of surface plasmons in silver films. Using near-field optical techniques, reflectivity, transmissivity, and scattering loss of the grooves were demonstrated.
Two teams, from the Institute of Physics, University of Basel, Switzerland, and from Laboratoire d’Optique PM Duffieux, Université de Franche-Comté, France, determined the values semiquantitatively. They found that the surface plasmon attenuation is dominated by material and surface/interface imperfections. The teams were comprised of A. Bouhelier, Th. Huser, H.-J. Güntherodt, and D.W. Pohl in Switzerland, and Fadi L. Baida and D. Van Labeke in France.
The whole article can be found online at Physical Review B. at the American Physical Society.