Plasmonic bandpass filters with cascaded rectangular ring resonators

Abstract

We theoretically present the analysis and design of a nanoplasmonic bandpass filter with flat-top spectral characteristics by cascading a series of directly connected rectangular ring resonators based on metal-insulator-metal waveguides. Analyzed by the equivalent lumped circuit model of the transmission line to plasmonic waveguides, the transmission properties of a symmetric rectangular ring resonator with the directly connected input and output waveguides are approximately the same as that of a Fabry-Perot resonator. Then the thin-film design methodology is applied to realize a plasmonic bandpass filter with the squared passband. An example of cascaded tworectangular ring resonator structure is numerically demonstrated by using the transmission line model and 2D finite difference time domain method. (C) 2014 Optical Society of America