Designing Plasmonic Eigenstates for Optical Signal Transmission in Planar Channel Devices

On-chip optoelectronic and all-optical information processing paradigms require compact implementation of signal transfer for which nanoscale surface plasmons circuitry offers relevant solutions. This work demonstrates the directional signal transmittance mediated by 2D plasmonic eigenmodes supported by crystalline cavities. Channel devices comprising two mesoscopic triangular input and output ports and sustaining delocalized, higher-order plasmon resonances in the visible to infrared range are shown to enable the controllable transmittance and routing between two confined entry and exit ports coupled over a distance exceeding 2 mu m. The transmittance is attenuated by >20 dB upon rotating the incident linear polarization, thus, offering a convenient switching mechanism. The optimal transmittance for a given operating wavelength depends on the geometrical design of the device that sets the spatial and spectral characteristic of the supporting delocalized modes. Our approach is highly versatile and opens the way to more complex information processing using pure plasmonic or hybrid nanophotonic architectures.