Numerical analysis of near-infrared plasmonic filter with high figure of merit based on Fano resonance

A near-infrared (NIR) plasmonic filter with a figure of merit as high as 321 is proposed and numerically investigated. The filter is realized by employing the nonlinear relationship between the waveguide resonant wavelength and the Fano resonance of the air and Si cavity. Because the cavity is directly coupled with metal-insulator-metal waveguides, the transmission efficiency (T) and optical resolution (FWHM) of the filter are both improved to a great extent, with T = 92% and FWHM = 5 nm, keeping choose wavelength within the NIR region. The transmission efficiency and optical resolution of our design may allow further applications in nanophotonic circuits. (C) 2017 The Japan Society of Applied Physics.