Calculation and optimization of electromagnetic resonances and local intensity enhancements for plasmon metamaterials with sub-wavelength double-slots

We propose two metamaterials with sub-wavelength double-slots ⌋ single-side double-slot metamaterial and double-side double-slot metamaterial. The dependence of the electromagnetic resonances and local intensity enhancements on the structural parameters is studied by thefnite-difference time-domain technique and thefnite element method. Results show that the central-arm of a double-slot structure strongly influences frequency and local intensities at both highand low-frequency resonances. Very strongfeld localization can be achieved at the high-frequency resonance and its particular distribution can be well controlled by the width of the central-arm. A double-side double-slot structure can be utilized to separately enhance the high-frequency resonance, while suppressing the low-frequency resonance. The simulation results are discussed in terms of plasmon resonances.