Terahertz Effective Magnetic Activity in Microstructured TiO 2 ; A Numerical Study

In this paper we show that a metamaterial realized from titanium oxide TiO 2 crystallized in anatase form mimics strong magnetic activity at terahertz frequencies. Due to its crystal structure, TiO 2 anatase presents active phonon modes in the far infrared wavelengths (or terahertz frequencies) leading to a high dielectric constant epsiv 0 =50 - 120 in the range of wavelengths lambda=100 - 40 mum. This leads to the presence of Mie resonances in a periodic array of cylinders made out of this material causing a strong effective magnetic response. Using the S-parameter formalism, we numerically investigate the electromagnetic properties of microstructured anatase, showing that this system presents effective negative permeability in the range of wavelengths lambda=80 - 40 mum.