Waveguide and radiation applications of modes in linear chains of plasmonic nanospheres

We apply an analytical procedure that uses a periodic Green´s function based on the Ewald representation to compute the modes in a linear chain of plasmonic nanospheres, including the case of complex modal wave numbers. We analyze both transverse and longitudinal polarizations (with respect to the array axis) of the nanospheres´ electric dipole moments. Among all the modes, we discuss those excitable and that can be used for wave guidance through bound modes or for radiation through leaky modes.