Local excitation of surface plasmon polaritons using nitrogen-vacancy centers

Surface plasmon polaritons (SPPs) are locally excited at silver surfaces using (∼100) nanometer-sized nanodiamonds (NDs) with multiple nitrogen-vacancy (NV) centers (∼400). The fluorescences from an externally illuminated (at 532 nm) ND and from nearby NDs, which are not illuminated but produce out-of-plane scattering of SPPs excited by the illuminated ND, exhibit distinctly different wavelength spectra, showing short-wavelength filtering due to the SPP propagation loss. The results indicate that NDs with multiple NV centers can be used as efficient subwavelength SPP sources in planar integrated plasmonics for various applications.