Compact disordered magnetic resonators designed by simulated annealing algorithm

Sub wavelength all-dielectric structures processing simultaneously electric and magnetic resonances provide a new horizon for tailoring magnetic light–matter interaction that is often overlooked in optical spectrum. In general, the magnetic field enhancement can be boosted by utilizing the magnetic resonances of dielectric resonators where structural disorder effect is considered as a parasitic negative effect for the targeted response. Here, in contrast, we theoretically propose and experimentally demonstrate that compact disordered dielectric resonators with substantial enhancement of free-space magnetic field can be automatically designed by the combination of simulated annealing algorithm and numerical solution of Maxwell’s equations, providing an alternative for tailoring magnetic light–matter interaction. The functionality and reliability of the proposed concept are further verified by microwave experiment. Our results might facilitate the application of compact disordered magnetic resonators in enhancing magnetic dipole transition of quantum emitter, magnetic resonance imaging, wireless power transfer and beyond.