| Specular reflectivity of the sinusoidally corrugated interface
for s–polarized incident waves and for different values of the groove depth to period ratio h/d.
Almost total absorptions occur for h/d = 0.012 at an angle of incidence θ=41.3 degree.
The evanescent order, which is phase matched with the ESW [Re α(h)= αl], is
represented by l=-1 in expantion (30). |
Map of | R-1 | as a function of θ and h/d. As it happens for metallic gratings and for
supporting only a propagating order, figure clearly indicates that the optimal excitation of ESW occurs at almost the same conditions as total
absorption and maximum local-field
enhancement. |
