Near-field characterisation of anisotropic all-dielectric terahertz resonators

We extract the intrinsic properties of micrometre-sized anisotropic dielectric resonators through near-field time-domain terahertz spectorscopy. Narrow terahertz resonances corresponding to magnetic dipole modes in ≈ 30µm-sized mono-crystalline TiO2 spheres split due to material anisotropy. Ensembles of TiO2 resonators can form complex meta-atoms for unusual electromagnetic response in terahertz all-dielectric metamaterials.