A Nanoscale Plasmonic Long-Wavelength Cutoff Filter

A nanoplasmonic cutoff filter consisting of two straight metal-insulator-metal waveguides connected with two symmetrical rectangular cavities (“+” type) is proposed and numerically simulated by using the finite difference time domain method with a perfectly matched layer absorbing boundary condition. The simulation demonstrates that the cutoff filter has characteristic of long-wavelength cutoff in the transmission spectrum. The cutoff wavelength increases with the increase of the two rectangular cavities length or the decrease of the width of the two rectangular cavities.