Dynamically Tunable Plasmon-Induced Transparency in On-chip Graphene-Based Asymmetrical Nanocavity-Coupled Waveguide System

Abstract

A graphene-based on-chip plasmonic nanostructure composed of a plasmonic bus waveguide side-coupled with a U-shaped and a rectangular nanocavities has been proposed and modeled by using the finite element method in this paper. The dynamic tunability of the plasmon-induced transparency (PIT) windows has been investigated. The results reveal that the PIT effects can be tuned via modifying the chemical potential of the nanocavities and plasmonic bus waveguide or by varying the geometrical parameters including the location and width of the rectangular nanocavity. Further, the proposed plasmonic nanostructure can be used as a plasmonic refractive index sensor with a sensing sensibility of 333.3 nm/refractive index unit (RIU) at the the PIT transmission peak. Slow light effect is also realized in the PIT system. The proposed nanostructure may pave a new way towards the realization of graphene-based on-chip integrated nanophotonic devices.

Optical Transport Properties of Graphene Surface Plasmon Polaritons in Mid-Infrared Band

“…As shown in Figure 4, L g and Im(β) are both negative at the substrate thicknesses of 15 and 20 nm when the wavelength is less than a certain value, which is because graphene SPPs cannot be excited under these conditions. Figure 3 shows the transmission characteristics on incident wavelengths for different applied voltages (1,2,3,4, and 5 V), and the incident wave is in the mid-infrared region (2500-25,000 nm). Here, Si is selected as the graphene substrate and dielectric material, and the substrate thickness is 10 nm.…”

“…Graphene surface plasmon polaritons have become the focus of current research because of their excellent properties and small footprint. Optical devices based on graphene surface plasmon polaritons have the advantages of a higher bandwidth, lower loss, and electric tunability [2,3].…”

Plasmon-induced transparency effect for ultracompact on-chip devices

“…Such two cavities can generate extreme destructive interference, which gives rise to the PIT response. In addition, the central wavelength can be tuned by the chemical potential of graphene, which avoids to design new structures [102][103][104][105][106]. In short, graphene is a potential candidate in constructing nanocavities for the PIT system due to its ultracompact size and ultrastrong field confinement.…”

Tunable Plasmon-Induced Transparency in Dual Hexagonal Resonators With Rotatable Embedded Bar

“…With the increase of integration requirements, many highly integrated photonic devices have to work at different frequencies. However, for most MIM waveguide PIT devices, the transparency windows are almost achieved at fixed wavelengths and they are barely modulated to different working frequencies [23]. Furthermore, in order to find more extensive and flexible applications of PIT device, other optical characteristics besides central wavelength such as transmission, bandwidth, and group index also should be able to be tuned [24].…”