Increasing the sensitivity of terahertz metamaterials for dielectric sensing by substrate etching

We investigate the effect of the effective substrate refractive index on the sensitivity of terahertz (THz) metamaterials for dielectric sensing by substrate etching. We found the effective refractive index near the metamaterials can be actively controlled by etching, allowing optimization of the sensitivity. Our experimental findings are in good agreement with finite element method (FEM) simulation results.