title: Active directional switching of surface plasmon polaritons using a phase transition material.
abstract: Active switching of near-field directivity, which is an essential functionality for compact integrated photonics and small optoelectronic elements, has been challenging due to small modulation depth and complicated fabrication methods for devices including active optical materials. Here, we theoretically and experimentally realize a nanoscale active directional switching of surface plasmon polaritons (SPPs) using a phase transition material for the first time. The SPP switching device with noticeable distinction is demonstrated based on the phase transition of vanadium dioxide (VO2) at the telecom wavelength. As the insulator-to-metal phase transition (IMT) of VO2induces the large change of VO2permittivity at telecom wavelengths, the plasmonic response of a nanoantenna made of VO2can be largely tuned by external thermal stimuli. The VO2-insulator-metal (VIM) nanoantenna and its periodic array, the VIM metagrating, are suggested as optical switches. The directional power distinction ratio is designed to change from 8.13:1 to 1:10.56 by the IMT and it is experimentally verified that the ratio changes from 3.725:1 to 1:3.132 as the VIM metagratings are heated up to 90 °C. With an electro-thermally controllable configuration and an optimized resonant design, we expect potential applications of the active switching mechanism for integrable active plasmonic elements and reconfigurable imaging.
authors.affiliation: Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanak-Gu Gwanakro 1, Seoul, 08826, Korea.
authors.forename: Sun-Je
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanak-Gu Gwanakro 1, Seoul, 08826, Korea.
authors.forename: Hansik
authors.initials: H
authors.lastname: Yun
authors.affiliation: Interdisciplinary Program of Biomedical Mechanical &Electrical Engineering and School of Electrical Engineering, Pukyong National University, Yongso-ro 45, Nam-Gu, Busan, 48513, South Korea.
authors.forename: Kyungsoo
authors.initials: K
authors.lastname: Park
authors.affiliation: Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanak-Gu Gwanakro 1, Seoul, 08826, Korea.
authors.forename: Jongwoo
authors.initials: J
authors.lastname: Hong
authors.affiliation: Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanak-Gu Gwanakro 1, Seoul, 08826, Korea.
authors.forename: Jeong-Geun
authors.initials: JG
authors.lastname: Yun
authors.affiliation: Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanak-Gu Gwanakro 1, Seoul, 08826, Korea.
authors.forename: Kyookeun
authors.initials: K
authors.lastname: Lee
authors.affiliation: Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanak-Gu Gwanakro 1, Seoul, 08826, Korea.
authors.forename: Joonsoo
authors.initials: J
authors.lastname: Kim
authors.affiliation: Interdisciplinary Program of Biomedical Mechanical &Electrical Engineering and School of Electrical Engineering, Pukyong National University, Yongso-ro 45, Nam-Gu, Busan, 48513, South Korea.
authors.forename: Sun Jae
authors.initials: SJ
authors.lastname: Jeong
authors.affiliation: Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanak-Gu Gwanakro 1, Seoul, 08826, Korea.
authors.forename: Sang-Eun
authors.initials: SE
authors.lastname: Mun
authors.affiliation: Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanak-Gu Gwanakro 1, Seoul, 08826, Korea.
authors.forename: Jangwoon
authors.initials: J
authors.lastname: Sung
authors.affiliation: Interdisciplinary Program of Biomedical Mechanical &Electrical Engineering and School of Electrical Engineering, Pukyong National University, Yongso-ro 45, Nam-Gu, Busan, 48513, South Korea.
authors.forename: Yong Wook
authors.initials: YW
authors.lastname: Lee
authors.affiliation: Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanak-Gu Gwanakro 1, Seoul, 08826, Korea.
authors.forename: Byoungho
authors.initials: B
authors.lastname: Lee