Highly confined surface plasmon polariton resonances in rectangular nanopore cavities

The excitation of surface plasmons in nanoslits in metal films is known to result in large electromagnetic field enhancements. The enhancement factor strongly depends on the exact geometrical parameters, such as widths and lengths. In this work, we numerically study field enhancement and transmission resonances inside short nanoslits (nanopores) with varying lengths using three-dimensional finite difference time domain (FDTD) simulations. The results indicate that the excitation of highly confined lateral Fabry-Perot surface plasmon resonances results in enhancement factors greatly exceeding the two-dimensional case. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim