Ultrahigh‐Q Fano Resonances in Terahertz Metasurfaces: Strong Influence of Metallic Conductivity at Extremely Low Asymmetry

Fano resonances in metasurfaces are important due to their low loss subradiant behavior that allows excitation of high-quality (Q) factor resonances extending from the microwave to the optical regime. High-Q Fano resonances have recently enabled applications in the areas of sensing, modulation, filtering, and efficient cavities for lasing spasers. Highly conducting metals are the most commonly used materials for fabricating the metasurfaces, especially at the low-frequency terahertz region where the DC, Drude, and perfect electric conductivity show similar resonant behavior of the subwavelength meta-atoms. Here, it is experimentally and theoretically demontrated that the Q factor of a low asymmetry Fano resonance is extremely sensitive to the conducting properties of the metal at terahertz frequencies. Large differences in the Q factor and figure of merit of the Fano resonance is observed for perfect electric conductors, Drude metal, and a DC-conducting metal, which is in sharp contrast to the behavior of the inductive–capacitive resonance of meta-atoms at terahertz frequency. Identification of such a low asymmetry regime in Fano resonances is the key to engineer the radiative and nonradiative losses in plasmonic and metamaterial-based devices that have potential applications in the microwave, terahertz, infrared, and the optical regimes.

[1]  Peter Nordlander,et al.  Symmetry breaking in plasmonic nanocavities: subradiant LSPR sensing and a tunable Fano resonance. , 2008, Nano letters.

[2]  N. Zheludev,et al.  Metamaterial analog of electromagnetically induced transparency. , 2008, Physical review letters.

[3]  D. Grischkowsky,et al.  2-D Terahertz Metallic Photonic Crystals in Parallel-Plate Waveguides , 2007, IEEE Transactions on Microwave Theory and Techniques.

[4]  Willie J Padilla,et al.  Terahertz Magnetic Response from Artificial Materials , 2004, Science.

[5]  Koray Aydin,et al.  Symmetry Breaking and Strong Coupling in Planar Optical Metamaterials References and Links , 2022 .

[6]  Yuri S. Kivshar,et al.  Optical activity and coupling in twisted dimer meta-atoms , 2012 .

[7]  Gennady Shvets,et al.  Fano-resonant asymmetric metamaterials for ultrasensitive spectroscopy and identification of molecular monolayers. , 2012, Nature materials.

[8]  Martin Koch,et al.  Sharp Fano resonances in THz metamaterials. , 2011, Optics express.

[9]  Yuri S. Kivshar,et al.  Fano Resonances in Nanoscale Structures , 2010 .

[10]  Weili Zhang,et al.  Effect of metal permittivity on resonant properties of terahertz metamaterials. , 2008, Optics letters.

[11]  P. Nussenzveig,et al.  Classical analog of electromagnetically induced transparency , 2001, quant-ph/0107061.

[12]  Willie J Padilla,et al.  Composite medium with simultaneously negative permeability and permittivity , 2000, Physical review letters.

[13]  Yuanmu Yang,et al.  All-dielectric metasurface analogue of electromagnetically induced transparency , 2014, Nature Communications.

[14]  Igal Brener,et al.  Spectrally selective chiral silicon metasurfaces based on infrared Fano resonances , 2014, Nature Communications.

[15]  Y. Wang,et al.  Plasmon-induced transparency in metamaterials. , 2008, Physical review letters.

[16]  P. Nordlander,et al.  The Fano resonance in plasmonic nanostructures and metamaterials. , 2010, Nature materials.

[17]  S. L. Prosvirnin,et al.  Coherent meta-materials and the lasing spaser , 2008, 0802.2519.

[18]  I. Al-Naib,et al.  Ultrasensitive terahertz sensing with high-Q Fano resonances in metasurfaces , 2014, 1406.7194.

[19]  N. Zheludev,et al.  Superconductor photonics , 2014, Nature Photonics.

[20]  Valerio Pruneri,et al.  Mid-infrared plasmonic biosensing with graphene , 2015, Science.

[21]  I. Al-Naib,et al.  Low-loss ultra-high-Q dark mode plasmonic Fano metamaterials. , 2012, Optics letters.

[22]  Ji Won Suk,et al.  Inductive tuning of Fano-resonant metasurfaces using plasmonic response of graphene in the mid-infrared. , 2013, Nano letters.

[23]  N I Zheludev,et al.  Sharp trapped-mode resonances in planar metamaterials with a broken structural symmetry. , 2007, Physical review letters.

[24]  Yuri S. Kivshar,et al.  Self-oscillations in nonlinear torsional metamaterials , 2013 .

[25]  F. Hesmer,et al.  Mapping inter-element coupling in metamaterials: Scaling down to infrared , 2012 .

[26]  Kaya Tatar,et al.  Electrical Switching of Infrared Light Using Graphene Integration with Plasmonic Fano Resonant Metasurfaces , 2015 .

[27]  J. Faist,et al.  High quality factor, fully switchable terahertz superconducting metasurface , 2014, 1411.3707.

[28]  J. Pendry,et al.  Magnetism from conductors and enhanced nonlinear phenomena , 1999 .

[29]  Yuri S. Kivshar,et al.  Metamaterial tuning by manipulation of near-field interaction , 2009, 0912.1152.

[30]  Roberto Morandotti,et al.  Effect of local field enhancement on the nonlinear terahertz response of a silicon-based metamaterial , 2013 .

[31]  Carsten Rockstuhl,et al.  The Fano Resonance in Symmetry Broken Terahertz Metamaterials , 2013, IEEE Transactions on Terahertz Science and Technology.

[32]  R. Shelby,et al.  Experimental Verification of a Negative Index of Refraction , 2001, Science.

[33]  Weili Zhang,et al.  Experimental demonstration of ultrasensitive sensing with terahertz metamaterial absorbers: A comparison with the metasurfaces , 2015 .

[34]  U. Chettiar,et al.  Loss-free and active optical negative-index metamaterials , 2010, Nature.

[35]  Transmission properties of double-gap asymmetric split ring resonators in terahertz region , 2012 .

[36]  Ibraheem Al-Naib,et al.  Fano Resonances in Terahertz Metasurfaces: A Figure of Merit Optimization , 2015 .

[37]  A. Bettiol,et al.  Tailoring the slow light behavior in terahertz metasurfaces , 2015, 1502.06684.

[38]  Weili Zhang,et al.  A Tunable Dispersion‐Free Terahertz Metadevice with Pancharatnam–Berry‐Phase‐Enabled Modulation and Polarization Control , 2015, Advanced materials.

[39]  V. Veselago.  The Electrodynamics of Substances with Simultaneously Negative Values of ∊ and μ , 1968 .

[40]  Harry A. Atwater,et al.  Low-Loss Plasmonic Metamaterials , 2011, Science.

[41]  D. Grischkowsky,et al.  Terahertz conductivity of thin metal films , 2008 .

[42]  U. Fano.  Effects of Configuration Interaction on Intensities and Phase Shifts , 1961 .

[43]  Zach DeVito,et al.  Opt , 2017 .

[44]  R. J. Bell,et al.  Optical properties of the metals Al, Co, Cu, Au, Fe, Pb, Ni, Pd, Pt, Ag, Ti, and W in the infrared and far infrared. , 1983, Applied optics.

[45]  Ke Wu,et al.  Polarization-Independent Metamaterial Analog of Electromagnetically Induced Transparency for a Refractive-Index-Based Sensor , 2012, IEEE Transactions on Microwave Theory and Techniques.