All-dielectric tunable zero-refractive index metamaterials based on phase change materials

We propose a tunable all-dielectric zero-index metamaterial based on phase change material. By constructing the alternating rod structure with phase change material and silica material, the zero-refractive index characteristic is realized. In order to verify the equivalent zero-index characteristic, we calculated the electromagnetic field distribution at center frequency. Based on phase invariance, it was found that this kind of metamaterial can achieve equivalent zero refractive index characteristics. To further achieve the polarization-insensitive zero refractive index, we propose a metamaterial structure based on the fishing nets structure. Based on the S-parameter inversion algorithm, the equivalent dielectric constant, equivalent permeability, equivalent impedance, and equivalent refractive index of the metamaterial were extracted. Based on the extracted equivalent parameters and the corresponding electromagnetic field distribution, the designed all-dielectric metamaterial has the tunable equivalent zero refractive index characteristic.