Improvement of unidirectional scattering characteristics based on multiple nanospheres array

All dielectric nanospheres with low loss and ultra-compact characteristics can be effectively applied in nanophotonics in the visible and infrared ranges. The unidirectional forward scattering with azimuthally symmetry can be achieved by simple dielectric nanosphere. The physical origin of this directionality can be attributed to the interference effect of electric and magnetic resonances induced in nanoshperes. For the forward scattering of a single nanosphere the spectrally overlapping resonance of electric and magnetic quadrupoles can further enhance the directionality and magnitude of unidirectional forward scattering. For a nanosphere homodimers, the scattering pattern can also preserve the azimuthal asymmetry and the suppression of backscattering. But, the side scattering lobes occur due to the grating diffraction effect. Furthermore, the significant improvement of scattering magnitude and directionality can be achieved by a linear chain of nanospheres. These unique optical scattering of nanoshperes can be applied in the fields of nanoantennas, photovoltaics, and nanolasers in visible and near infrared ranges.