Forbidden guided-wave plasmon polaritons in coupled thin films

Abstract

Forbidden guided wave plasmon polaritons in a three thin film on a substrate structure were studied. The structure supported polaritons that can exist only in a normally forbidden region of the surface polariton dispersion. The collective modes were found to emerge from surface and bulk mode bands and evolve into a ladder of solutions in the forbidden region. The attenuated total reflection (ATR) spectrum arising from the guided modes was also presented.