A subwavelength plasmonic waveguide filter with a ring resonator

Abstract

The transmission characteristics of the electromagnetic wave are numerically investigated in two-dimensional compound plasmonic structures composed of two straight subwavelength metal-insulator-metal (MIM) waveguides and a ring resonator. The two straight MIM waveguides situate on both sides of the ring resonator, and the MIM waveguide of the outgoing side has a positional angular deviation θ relative to the MIM waveguide of the incoming side. The results show that the filtering performances of the asymmetric structures (θ ≠ 0 °) are greatly improved in comparison with the symmetric structure (θ = 0 °). For most of the asymmetric structures, there is a transmission minimum at the slightly bigger wavelength than one at which the transmission peak appears for the symmetric structures, and there is still a transmission peak at the wavelength of the transmission peak of the symmetric structures. Moreover, the difference between the transmission peak and valley is increased, and the breadth of the transmission peak becomes narrow. © 2013 Xiang Zhai et al.