title: Fast tuning of double Fano resonance using a phase-change metamaterial under low power intensity.
abstract: In this work, we numerically demonstrate an all-optical tunable Fano resonance in a fishnet metamaterial(MM) based on a metal/phase-change material(PCM)/metal multilayer. We show that the displacement of the elliptical nanoholes from their centers can split the single Fano resonance (FR) into a double FR, exhibiting higher quality factors. The tri-layer fishnet MMs with broken symmetry accomplishes a wide tuning range in the mid-infrared(M-IR) regime by switching between the amorphous and crystalline states of the PCM (Ge2Sb2Te5). A photothermal model is used to study the temporal variation of the temperature of the Ge2Sb2Te5 film to show the potential for switching the phase of Ge2Sb2Te5 by optical heating. Generation of the tunable double FR in this asymmetric structure presents clear advantages as it possesses a fast tuning time of 0.36 ns, a low pump light intensity of 9.6 μW/μm(2), and a large tunable wavelength range between 2124 nm and 3028 nm. The optically fast tuning of double FRs using phase change metamaterials(PCMMs) may have potential applications in active multiple-wavelength nanodevices in the M-IR region.
authors.affiliation: Department of Biomedical Engineering, Dalian University of Technology, China(P.R.C).
authors.forename: Tun
authors.initials: T
authors.lastname: Cao
authors.affiliation: Department of Biomedical Engineering, Dalian University of Technology, China(P.R.C).
authors.forename: Chenwei
authors.initials: C
authors.lastname: Wei
authors.affiliation: Singapore University of Technology and Design (SUTD), 20 Dover Drive, Singapore.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Simpson
authors.affiliation: Department of Biomedical Engineering, Dalian University of Technology, China(P.R.C).
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Electrical and Electronic Engineering, University of Bristol, Bristol, UK.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Cryan