Resonant broadband unidirectional light scattering based on genetic algorithm

The spectrum overlapping of the radiative power between magnetic and electric dipole moments in nanoparticles can be used to realize unidirectional light scattering, which is promising for various kinds of applications. Nevertheless, it is still challenging to achieve such overlapping in a broadband manner. Herein, we propose that the combination of a genetic algorithm, Maxwell's equations, and electromagnetic multipole expansion can be used to design a nanoparticle that supports resonant broadband forward light scattering. Microwave experiments are performed to demonstrate our numerical results. The proposed method is quite general, and it can be straightforwardly generalized to design functional unidirectional scatters.