title: Tunable tapered waveguide for efficient compression of light to graphene surface plasmons.
abstract: Dielectric-graphene-dielectric (DGD) structure has been widely used to construct optical devices at infrared region with features of small footprint and low-energy dissipation. The optical properties of graphene can be manipulated by changing its chemical potential by applying a biased voltage onto graphene. However, the excitation efficiency of surface wave on graphene by end-fire method is very low because of large wavevector mismatch between infrared light and surface wave. In this paper, a dielectric-semiconductor-dielectric (DSD) tapered waveguide with magnetic tunability for efficient excitation of surface waves on DGD at infrared region is proposed and analyzed. Efficient excitation of surface waves on DGD with various chemical potentials in graphene layer and incident frequencies can be attained by merely changing the external magnetic field applied onto the DSD tapered waveguide. The electromagnetic simulations verify the design of the proposed structure. More importantly, the constituent materials used in the proposed structure are available in nature. This work opens the door toward various applications in the field of using surface waves.
authors.affiliation: Department of Electro-Optical Engineering, National Taipei University of Technology, Taipei 106, Taiwan.
authors.forename: Bo Han
authors.initials: BH
authors.lastname: Cheng
authors.affiliation: Department of Photonics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Taiwan 70101, Taiwan.
authors.forename: Hong Wen
authors.initials: HW
authors.lastname: Chen
authors.affiliation: Department of Electro-Optical Engineering, National Taipei University of Technology, Taipei 106, Taiwan.
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Jen
authors.affiliation: Department of Photonics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Taiwan 70101, Taiwan.
authors.forename: Yung-Chiang
authors.initials: YC
authors.lastname: Lan
authors.affiliation: Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan.|Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Din Ping
authors.initials: DP
authors.lastname: Tsai