Fundamental Properties of Mie Resonances in Water Spheres

All-dielectric metamaterials constitute an interesting route in the artificial material design due to their low-loss properties. Such constructs require high permittivity materials which support the excitation of Mie resonances, thereby enabling the underlying inclusions to be of small electrical sizes. Optics mostly relies on silicon, while several materials are used in the microwave range. Presently, we consider the potential of simple water as the inclusion in practical artificial materials due to its high permittivity and tunable dynamic properties through e.g., frequency and temperature variations. To this end, we undertake an analytical study of Mie resonances in water spheres and examine primarily the effects of frequency and temperature variation on the excitation and isolation of electric and magnetic dipoles. We also demonstrate directive patterns in forward and backward directions in water spheres with balanced electric/magnetic dipole excitations. As such, our results may not only be used directly in or as a guideline for metamaterial design, but they may also pave the way for simple and directive antennas.