Band-pass plasmonic slot filter with band selection and spectrally splitting capabilities.

An ultra-compact surface plasmon polaritons (SPPs) narrow band-pass filter based on a slot cavity is proposed and numerically investigated. Attributed to the coupled resonances in the cavity, the filter demonstrates pass-band selection capability. Also, by varying the positions of output waveguides, the filter shows the spectrally splitting function. Moreover, the combination of the adjustments to the length/width of the slot cavity and to the coupling distance provides more flexibility in design for the locations and widths of the pass-bands of the proposed filter.