Asymmetric SPP waveguide without sacrificing the size of subwavelength waveguide

A multifunction filter based on plasmonic waveguide with double-nanodisk-shaped resonators

“…Surface plasmon polaritons (SPPs) are electromagnetic waves coherently coupled to electron oscillation and propagating along a metal-dielectric interface with an exponentially decaying field in both sides, have been considered as energy and information carriers to overcome the diffraction limit of light in conventional optics [1][2][3]. Based on SPPs, a number of metalinsulator-metal (MIM) structures have been numerically simulated and/or experimentally demonstrated, such as plasmonic filter [2][3][4][5], wavelength demultiplexing structures [1,6], Mach-Zehnder interferometers [7,8], sensors [9,10], nanolenses [11], splitters [12], and Y-shaped combiners [13].…”

“…Based on SPPs, a number of metalinsulator-metal (MIM) structures have been numerically simulated and/or experimentally demonstrated, such as plasmonic filter [2][3][4][5], wavelength demultiplexing structures [1,6], Mach-Zehnder interferometers [7,8], sensors [9,10], nanolenses [11], splitters [12], and Y-shaped combiners [13]. These devices may be fabricated and applied in future optical communications and integrated optical circuits with the development of nanofabrication and nanocharacterization capabilities [5].…”

“…As one of the most important devices in optical communications and one of the key components in the nanoscale integration platform, plasmonic filters based on MIM waveguides have been studied widely in recent years [1,5], such as ring and nanodisk resonators [14,15], rectangular resonator structures [3,4], plasmonic grating [16], and stub or tooth-shaped waveguide filter [5,17]. All these structures can only realize a channel drop filtering function or have tunable resonance wavelengths [5].…”

“…In practical applications, the wavelength division multiplexing (WDM) plays an important role in signal processing in optical communications. In WDM systems, it is necessary to separately select several specific wavelengths in different channels [1]. Therefore, how to realize wavelengths selection in different channels is the priority mission in plas- mon devices [2].…”

“…In order to realize this function, some plasmonic demultiplexing devices have been proposed. For example, Hu et al [1] designed a structure of plasmonic slot cavities arrays capable of wavelength division multiplexing but it has high transmittance loss. To reduce transmittance loss, a plasmonic nanodisk filter with mode inhibition and spectrally splitting capabilities is designed but it only has two operating wavelengths [2].…”