Ultrafast and Low-Power Dynamically Tunable Plasmon-Induced Transparencies in Compact Aperture-Coupled Rectangular Resonators

In this paper, ultrafast and low-power dynamically tunable single and multiple plasmon-induced transparencies in ultracompact rectangular resonators aperture-coupled metal-dielectric-metal (MDM) waveguide system with nonlinear optical Kerr medium is investigated both analytically and numerically. Multiple PITs are realized in this plasmonic waveguide structure based on bright-dark mode coupling mechanism. High tunability in transparency window magnitude, phase shift, and group index is obtained when nonlinear optical Kerr material is embedded in the MDM waveguide. In order to reduce the pump intensity, traditional nonlinear optical Kerr material is replaced by graphene. A shift of 45 nm in the central wavelength of the single transparency window is achieved when the rectangular resonators are covered by monolayer graphene with pump intensity increasing from 6.7 to 7.5 MW/cm
²
. Calculated results show that whole structure is ultracompact with the footprint of <0.5 μm
²
and an ultrafast response time of the order of 1 ps can be reached.