  All-dielectric metamaterials composed of high index and low loss dielectric
resonators have become a promising way for high-efficient optical devices.
However, fabricating terahertz all-dielectric metamaterials and actively tuning
their properties still remain challenges. In this paper, an effective method
has been developed to prepare high-quality microspheres based all-dielectric
metamaterial operating in terahertz (THz) range. Then, we propose a
magnetically tunable THz all-dielectric metamaterial based on liquid crystal
(LC). The all-dielectric metamaterial is immersed into LC and tuned by external
magnetic field. We show that the induced Mie resonances can be effectively
tuned by external magnetic field and the tunability is highly sensitive to the
directors of applied magnetic field. A good tunability performance is obtained
for the first electric resonance. This work provides a new method for
high-quality THz all-dielectric metamaterials and paves a promising way for
tunable THz all-dielectric metamaterial, which would find considerable
applications in THz devices.
