Nanoscale Color Sorting of Surface Plasmons in a Double-Nanogap Structure with Multipolar Plasmon Excitation

We demonstrated a new plasmonic nanodevice that spatially sorts photons according to their colors on the nanoscale while maintaining their nano concentration. The properties of this nanoscale color sorting based on constructive and destructive interferences between different multipolar plasmon modes are controlled by tuning the incidence angle of the incoming photons. The added ability of color sorting and its manipulation could significantly influence the development of possible photonic applications, including nanoscale spectroscopy and sensing.