Absorption property and nanosensing via double metal films with rectangle holes array

A theoretical investigation of plasmonic absorption and nanosensing based on a three dimensional nanostructure is presented. The structure consists of double metal films covered with rectangle nanoholes array. A dielectric layer is located between the double metal films with the function of confining electromagnetic fields. Optical absorption properties of the designed nanostructure are investigated by finite-difference time-domain method, obvious peaks appear in the absorption spectra is due to the Fabry-Perot resonance effect and localized surface plasmon resonance of the rectangle nanoholes. The absorption spectra dependence on the environmental and dielectric layer refractive index, which makes it an outstanding candidate for nanosensing. The results of this study may have potential application in absorption switching and nanosensors.