Switchable surface plasmon dichroic splitter modulated by optical polarization

For the miniaturization of optical devices, surface plasmon polaritons (SPPs) have been widely utilized due to their outstanding confinement and field-enhancement characteristics. Analyzing a spectrum of optical signals and splitting certain regions of the spectrum range within a submicrometer-scale structure are demanded for optical integrated systems. In this paper, a novel type of dichroic surface plasmon launcher that can switch the launching direction according to incident polarization states is demonstrated. Compared to the previously reported plasmonic dichroic splitters, the proposed schemes do not use any asymmetric geometry for directional launching. Hence, the direction of guided SPPs can be interchanged according to the polarization state. Such characteristics will be helpful to design switchable plasmonic devices that can be applied to active plasmonic integrated circuits. A submicron plasmonic dichroic splitter, which is used for not only guiding two desired wavelengths in opposite directions but also interchanging the launching direction according to the incident polarization state, is demonstrated. The principle of the device, based on the directional launching phenomenon and Fabry-Pérot resonance in a nanoslit, will be helpful to design various types of switchable plasmonic devices.