Tuning the Resonance in High-Temperature Superconducting Terahertz Metamaterials

MPA-CINT, MS K771, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Physical Review Letters (Impact Factor: 7.73). 12/2010; 105(24):247402. DOI: 10.1103/PhysRevLett.105.247402
Source: arXiv

ABSTRACT In this Letter, we present resonance properties in terahertz metamaterials consisting of a split-ring resonator array made from high-temperature superconducting films. By varying the temperature, we observe efficient metamaterial resonance switching and frequency tuning. The results are well reproduced by numerical simulations of metamaterial resonance using the experimentally measured complex conductivity of the superconducting film. We develop a theoretical model that explains the tuning features, which takes into account the resistive resonance damping and additional split-ring inductance contributed from both the real and imaginary parts of the temperature-dependent complex conductivity. The theoretical model further predicts more efficient resonance tuning in metamaterials consisting of a thinner superconducting split-ring resonator array, which are also verified in subsequent experiments.

Download full-text


Available from: Quanxi Jia, Dec 20, 2013
1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A superconducting metasurface operating in the THz range and based on the complementary metamaterial approach is discussed. Experimental measurements as a function of temperature and magnetic field display a modulation of the metasurface with a change in transmission amplitude and frequency of the resonant features. Such a metasurface is successively used as a resonator for a cavity quantum electrodynamic experiment displaying ultrastrong coupling to the cyclotron transition of a 2DEG. A finite element modeling is developed and its results are in good agreement with the experimental data. In this system a normalized coupling ratio of $\frac{\Omega}{\omega_c}=0.27$ is measured and a clear modulation of the polaritonic states as a function of the temperature is observed.
    New Journal of Physics 11/2013; 16(3). DOI:10.1088/1367-2630/16/3/033005
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We characterized and compared the electromagnetically induced transparency (EIT) response of superconducting niobium nitride (NbN) and NbN–Au hybrid metamaterials. In our design, the two resonators in a unit cell have strong coupling and are directly excited under terahertz (THz) radiation. A stronger slow light effect was achieved using superconducting metamaterials than hybrid metamaterials. The enhanced slow light effect could be attributed to the remarkably low Ohmic loss and strong interaction of the resonators.
    Superconductor Science and Technology 05/2013; 26(7):074004. DOI:10.1088/0953-2048/26/7/074004
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present the nonlinear response of superconducting niobium nitride (NbN) thin film and NbN metamaterial with different thicknesses under intense terahertz pulses. For NbN thin film, nonlinearity emerges and superconductivity is suppressed with increasing incident terahertz electric field, and the suppression extent weakens as the film thickness increases from 15 to 50 nm. As the variation in intense terahertz fields alters the intrinsic conductivity in NbN, a consequent remarkable amplitude modulation in NbN metamaterial is observed due to the strong nonlinearity. Absorbed photo density in either NbN film or NbN metamaterial is estimated and used to understand the mechanism of nonlinear response. With a thicker NbN film element of 200 nm, the resonance of the metamaterial shows similar nonlinear modulation accompanied by a lower loss and a higher quality factor compared with a thinner NbN film element of 50 nm, which demonstrates the innovative implementation of strongly enhanced nonlinearity with thick superconducting film elements and the potential for novel applications using nonlinear metamaterial.
    New Journal of Physics 05/2013; 15(5):055017. DOI:10.1088/1367-2630/15/5/055017