We study the broadband scattering of light by composite nanoparticles through the Born approximation, FEM simulations, and measurements. The particles consist of two materials and show broadband directional scattering. From the analytical approach and the subsequent FEM simulations, it was found that the directional scattering is due to the phase difference between the fields scattered by of each of the two materials of the nanoparticle. To confirm this experimentally, composite nanoparticles were produced using ion-beam etching. Measurements of SiO₂ / Au composite nanoparticles confirmed the directional scattering which was predicted by theory and simulations.

We show that composite nanoparticles can be designed to scatter light into a desired direction. By choosing the materials of the nanoparticle carefully, the phase of the scattered light by the different components can be controlled. This leads to constructive interference is certain directions and destructive interference in others, resulting in directional scattering obtainable for a large bandwidth. FEM simulations were used to validate the theory. Furthermore, SiO2/Au nanoparticles were fabricated and measured confirming the directional scattering.

We show that the scattering of light by a composite nanoparticle leads to directional scattering through the phase difference between the light scattered by each of the materials. The resulting scatter pattern is experimentally verified.