Competing nonlinearities with metamaterials

We suggest an approach for creating metamaterials with sign-varying nonlinear response. We demonstrate that microwave metamaterials with such competing nonlinearities can be created by loading split-ring resonators (meta-atoms of the structure) with pairs of varactor diodes and photodiodes exhibiting nonmonotonic resonance frequency shift with changing incident microwave power. Additionally, the nonlinear response of such metamaterials can be controlled by illuminating the meta-atoms by light. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768945]