Expanding the band of negative permeability of a composite structure with dual-band negative permeability.

We provide a design of a metallic composite structure, which simultaneously shows dual-band negative permeability (DNP) in two optical ranges. Numerical simulation demonstrates that different shifting of the two magnetic resonances can be observed. This structure property allows the realization of a wide range of negative permeability covering near-infrared (NIR) and visible ranges simultaneously. The alterability of the two neighboring negative permeability would provide a way to realize an effective pass-band of a meta-material with negative permeability at optical frequencies. (C) 2008 Optical Society of America