We report a highly efficient graphene-based modulator by using an edge plasmonic effect in this paper. The modulation efficiency of the proposed modulator can be as large as 1.58 dB/μm, which is several times larger than that of previous reported modulators. By enhancing the gap plasmon mode and the edge plasmonic effect in a well-designed diagonal waveguide, a wedge-to-wedge SPP mode is strongly confined in both horizontal and vertical directions in terms of a small mode area (A eff /A 0 < 1/1000), which significantly improves the light-graphene interaction. A large modulation efficiency of 4.05 dB/μm has been obtained after geometry optimization, which is the best values reported in our knowledge. The physical reason for the improvement is explored. We find the sharpness of the waveguide edges has strong impact on the field enhancement and modulation efficiency. Geometry optimization is made to further investigate the enhancement mechanisms and modulation capacities. Our results may promote the development of active nanophotonic devices incorporating two-dimensional materials.
A metal-insulator-metal (MIM) structure which is used to enhance the focusing energy of planar lens is developed in this work. The top of the MIM structure is formed by circularly arranged V-shaped nanoantennas whose double resonance effect makes it possible for light to obtain great phase changes within an ultra-thin area. The middle and bottom of the structure is medium and gold film layer respectively. This structure produces plasmonic coupling between the antenna layer and gold film, thus reducing Ohmic loss and enhancing the effect of plasmonic excitation. When the distance between the antenna layer with a thickness of 30 nm and gold film is 88 nm, and the thickness of gold film is 20 nm, the enhancement of plasmonic coupling reaches to the strongest when the focusing intensity is 1.33 times higher than the lens only. With the advantages of small size, ultra-thin, great phase changes and high-efficient focusing ability, the enhanced plasmonic coupling lens structure can be widely applied in photoetching, and integrated optics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.