Switching nonlinearity in a superconductor-enhanced metamaterial
  We demonstrate a nonlinear metamaterial that can be switched between low and high transmission by controlling the power level of the incident beam. The origin of this nonlinear response is the superconducting Nb thin film employed in the metamaterial structure. We show that with moderate RF power of about 22 dBm it is possible to quench the superconducting state as a result of extremely strong current densities at the corners of the metamaterial's split-ring resonators. We measure a transmission contrast of 10 dB and a change in group delay of 70 ns between the low and high power states. 
Cihan Kurter, Philippe Tassin, Alexander P. Zhuravel, Lei Zhang,   Thomas Koschny, Alexey V. Ustinov, Costas M. Soukoulis, S...
cond-mat.mtrl-sci cond-mat.supr-con physics.optics