On surface-plasmon-polariton waves excited in the Turbadar-Otto configuration

A local minimum in the plot of linear reflectance versus angle of incidence, on its own, is insufficient to identify a surface-plasmon-polariton wave (SPPW). Further checks are required in order to confirm the identity of a SPPW. The wavenumber should be compared with that extracted from the dispersion relation for the corresponding canonical boundary-value problem. Also, for prism-coupled configurations such as the Turbadar–Otto configuration which are based on SPPW-excitation via evanescent waves, the angle of incidence should be greater than the critical angle needed for total internal reflection.