Optical resonances in Kretschmann and Otto configurations.

This Letter revises the resonance theory of Kretschmann and Otto configurations, where enhanced electromagnetic fields and strong reflectance dips observed under total internal reflection are conventionally attributed to the resonance on surface plasmon-polaritons, the subsystem eigenwaves supported by a single metal/dielectric interface. The rigorous mathematical analysis demonstrates that the field enhancement and reflection decrease, in fact, are two independent physical phenomena that occur under different conditions. Moreover, neither of them coincides with the resonance on surface plasmon-polaritons that manifests in Kretschmann and Otto configurations through other distinct optical effect.