Numerical study of a new negative index material in mid-infrared spectrum

We explored numerically a new negative index material in mid-infrared spectrum, based on a thin wire net pairs and a square ring pairs array, which exhibits simultaneously hyper-transmission, polarization independence and small period. The mechanism implementing the negative refractive index was analyzed using retrieved optical constants as well as a valid analytical expression of the effective permeability that was deduced by virtue of a simple equivalent circuit model and applied to account for the magnetic property of this metamaterial.