A Nanoplasmonic High-PassWavelength Filter Based on a Metal-Insulator-Metal Circuitous Waveguide

A nanoplasmonic high-pass wavelength filter consisting of two straight metal-insulator-metal waveguides side-connected with a dielectric islet to form a circuitous waveguide is proposed and simulated numerically by using the finite difference time domain method. The simulation demonstrates that the plasmonic filter is characterized as a high-pass wavelength filter in the transmission spectrum. The cutoff wavelength increases with the increase of the length or the decrease of the width of the dielectric islet. Explanation of the high-pass filtering effect is given with a theoretical expression of the cutoff wavelength.