Design of a maximally flat optical low pass filter using plasmonic nanostrip waveguides.

In this paper, we present a new optical range low pass filter based on plasmonic nanostrip waveguides. We calculate the characteristic impedance of plasmonic nanostrip waveguides and compare it with that of microstrip transmission lines. An optical range maximally flat low pass filter with subwavelength dimensions is designed based on the nanostrip waveguide structure. Finite-difference time-domain (FDTD) simulations of the designed optical range filter are presented, which demonstrate subwavelength light confinement as well as acceptable filter cutoff performance.