A submicron surface-plasmon-polariton dichroic splitter based on a composite cavity structure


By integrating a vertical cavity into an asymmetric nanoslit, we demonstrate numerically and experimentally that such a composite cavity structure is capable of generating and splitting surface plasmon polaritons (SPPs) of two different wavelengths to opposite directions. The reason is that the horizontal cavity in the upper part of the asymmetric nanoslit and the added vertical cavity can manipulate SPPs nearly independently. High splitting ratios of 1:24 and 23:1 at splitting wavelengths of 767 nm and 847 nm are numerically presented with a device lateral dimension of only 790 nm. Moreover, the splitting wavelengths can easily be tuned. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794803]