Controlled plasmon resonance in closed metal/insulator/metal nanocavities

The controlled plasmon resonance in nanometer-sized optical cavities with a closed end has been demonstrated. A nanosheet plasmon cavity is a metal/insulator/metal waveguide with a finite length. Its lowest-order transverse-magnetic guided mode is reflected at the ends and exhibits the Fabry-Perot resonance. In this study, one of the ends was closed by an obliquely evaporated Au film, and the so-called organ pipe resonances were observed as reflection dips. Since such closed configurations offer a higher field enhancement and higher detection efficiency of the scattered light, they are promising as fundamental structures for Raman enhancement. (c) 2006 American Institute of Physics.