Engineering all-dielectric nanoparticles for tuning the electric and magnetic dipole resonances and enhancing magnetic dipole emission (Conference Presentation)

Abstract

Efficient control of light-matter interactions requires simultaneous manipulations of both electric and magnetic field components of light. For plasmonic nanoparticles, the electric interactions dominate while the magnetic counterparts are relatively weak. In addition, dissipative losses in plasmonic nanoparticles are large, making the realization of high-efficiency devices difficult. In order to solve these problems, high-index dielectric nanostructures arise as promising low-loss candidates with equally strong electric and magnetic resonances in the visible spectrum. In this presentation, based on numerical simulations, we will demonstrate our recent results on spectral tuning of the electric and magnetic dipole (ED and MD) resonances by arranging amorphous silicon nanoparticles into a periodic array. By forming a rectangular array with different periodicities in the x- and y-axis, the ED and MD resonances are separately coupled and effectively engineered. With this method, a variety of optical applications and devices can be accomplished, e.g. to improve the detection performance of a biosensor based on the MD resonance of a silicon nanoparticle and to realize a full 2π phase control in dielectric metasurfaces. Interestingly, it is also possible to achieve a MD resonance with sub-10 nm linewidth and an enhancement factor for the magnetic field intensity larger than one order of magnitude compared to a single isolated particle. Furthermore, based on this arrangement we will show a record high emission enhancement of a magnetic dipole source in an array of hollow silicon nanocylinders. An enhancement factor by three orders of magnitude can be obtained compared to a MD emitter in free space.