Flexible Visible-Infrared Metamaterials and Their Applications in Highly Sensitive Chemical and Biological Sensing
ABSTRACT Flexible electronic and photonic devices have been demonstrated in the past decade, with significant promise in low-cost, light-weighted, transparent, biocompatible, and portable devices for a wide range of applications. Herein, we demonstrate a flexible metamaterial (Metaflex)-based photonic device operating in the visible-IR regime, which shows potential applications in high sensitivity strain, biological and chemical sensing. The metamaterial structure, consisting of split ring resonators (SRRs) of 30 nm thick Au or Ag, has been fabricated on poly(ethylene naphthalate) substrates with the least line width of ∼30 nm by electron beam lithography. The absorption resonances can be tuned from middle IR to visible range. The Ag U-shaped SRRs metamaterials exhibit an electric resonance of ∼542 nm and a magnetic resonance of ∼756 nm. Both the electric and magnetic resonance modes show highly sensitive responses to out-of-plane bending strain, surrounding dielectric media, and surface chemical environment. Due to the electric and magnetic field coupling, the magnetic response gives a sensitivity as high as 436 nm/RIU. Our Metaflex devices show superior responses with a shift of magnetic resonance of 4.5 nm/nM for nonspecific bovine serum albumin protein binding and 65 nm for a self-assembled monolayer of 2-naphthalenethiol, respectively, suggesting considerable promise in flexible and transparent photonic devices for chemical and biological sensing.
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ABSTRACT: We demonstrate a proof of principle that plasmonic Fano resonance can provide a complementary enhancement mechanism boosting the absorption efficiency of thin metamaterial solar absorbers over a wide angle of incidence under both TE and TM polarizations. Fano resonances are induced in arrays of two asymmetric metallic nanodimers coupled to a metallic layer through an intermediate insulator thin film. The resulting moderate resonant peaks shown in the scattering spectrum are predicted to play a dominant role in light-trapping enhancement.Journal of the Optical Society of America B 04/2015; 32(4). DOI:10.1364/JOSAB.32.000595 · 1.81 Impact Factor
Applied Physics Letters 02/2015; 106(6):061906. DOI:10.1063/1.4908253 · 3.52 Impact Factor
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ABSTRACT: In order to investigate the effects of bending strain on electric-magnetic coupling, we fabricated and characterized two types of flexible terahertz (THz) metamaterials on polyethylene naphthalate (PEN) substrates, which had either asymmetric or symmetric configuration. The asymmetric flexible THz metamaterials showed a plasmon-induced transparency originating from electric-magnetic coupling. The transparency was rather robust and insensitive to strain. The symmetric metamaterials demonstrated a transmission dip at a frequency of 1.35 THz without applied strain due to electric resonance. However, if strain gradually varied, a continuously tunable transmission dip was observed at a frequency of 1.1 THz, which could be ascribed to electric-magnetic coupling induced by symmetry breaking. The promising results suggested that the asymmetric and the symmetric flexible THz metamaterials could find potential applications in curved devices and remote stress sensors, respectively.Plasmonics 01/2015; DOI:10.1007/s11468-015-9940-3 · 2.74 Impact Factor