Cavity modes and surface plasmon waves coupling on nanostructured surfaces for enhanced sensing and energy applications

Surface electromagnetic waves, in general, and surface plasmon waves, in particular, are by their nature strongly localized and confined to the surface on which they are excited; hence, enhancement of their field near the surface occurs. Generating strong local fields is the main subject of this chapter and can be summarized into three main parts. A new technique for designing a self-referenced sensor, which involves the excitation of two optical modes, is discussed based on a thin dielectric grating on thin metal film geometry. Besides the surface plasomnic modes, metallic gratings can support the excitation and even the coupling of cavity modes to surface plasomnic modes, depending on the conditions and the parameters of the grating. In addition, this chapter involves using the two surface plasmon phenomena (extended and localized) and the cavity mode to discuss a unique technique for generating enhanced fields over a wide range of wavelengths that can be utilized in sensing (simultaneously operating in the visible and infra-red regimes), spectroscopic, and energy applications based on metallic gratings. Finally, the relationship between the field enhancement in a plasmonic system and the observed splitting in the energy spectrum in the system of metallic nanoparticles on metal film (called MNPs-MF geometry) is thoroughly investigated due to its fundamental and practical importance.