Magnetic-free nonreciprocal photonic platform based on time-modulated graphene capacitors

作     者：D. Correas-Serrano A. Alù J. S. Gomez-Diaz 

作者机构：Department of Electrical and Computer Engineering University of California Davis One Shields Avenue Kemper Hall 2039 Davis California 95616 USA Photonics Initiative Advanced Science Research Center City University of New York 85 St. Nicholas Terrace New York City New York 10031 USA Physics Program Graduate Center City University of New York New York New York 10016 USA and Department of Electrical Engineering City College of the City University of New York New York New York 10031 USA 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2018年第98卷第16期

页      面：165428-165428页

核心收录：

基　　金：National Science Foundation, NSF, (1749177) Air Force Office of Scientific Research, AFOSR National Science Foundation, NSF 

主　　题：Photonics Plasmonics Graphene Waveguides Lorentz symmetry 

摘      要：We propose a paradigm for the realization of nonreciprocal photonic devices based on time-modulated graphene capacitors coupled to photonic waveguides, without relying on magneto-optic effects. The resulting hybrid graphene-dielectric platform is low loss, silicon compatible, robust against graphene imperfections, scalable from terahertz to near-infrared frequencies, and it exhibits large nonreciprocal responses using realistic biasing schemes. We introduce an analytical framework based on solving the eigenstates of the modulated structure and on spatial coupled mode theory, unveiling the physical mechanisms that enable nonreciprocity and enabling a quick analysis and design of optimal isolator geometries based on synthetic linear and angular momentum bias. Our results, validated through harmonic-balance full-wave simulations, confirm the feasibility of the introduced low-loss (3 dB) platform to realize large photonic isolation through various mechanisms, such as narrow-band asymmetric band gaps and interband photonic transitions that allow multiple isolation frequencies and large bandwidths. We envision that this technology may pave the wave to magnetic-free, fully integrated, and CMOS–compatible nonreciprocal components with wide applications in photonic networks and thermal management.