Abstract-Giant nonlinearity in a superconducting sub-terahertz metamaterial

V. Savinov1,a), K. Delfanazari1, V. A. Fedotov1 and N. I. Zheludev1,2

1 Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Southampton, SO17 1BJ, United Kingdom

2 Centre for Disruptive Photonic Technologies, TPI, Nanyang Technological University, Singapore 637371, Singapore

a) vs1106@orc.soton.ac.uk

Appl. Phys. Lett. 108, 101107 (2016);

 http://dx.doi.org/10.1063/1.4943649

We report a superconducting sub-THz metamaterial operating in a CW-regime, which exhibits a record-breaking resonant third-order nonlinearity with effective n2∼10 cm2/W$n_2\sim 10\hspace{0.17em}{\text{cm}}^2/\mathrm{W}$. The nonlinear response is caused by the radiation-induced resistive heating, suppressing the superconductivity in the nano-scale constrictions of the structure's meta-molecules. The nonlinearity has a relaxation time of 25 μs$25\hspace{0.17em}\mu \mathrm{s}$ and leads to a substantial change of the amplitude and phase of the transmitted radiation at intensities of only 500 μW/cm2$500\hspace{0.17em}\mu {\mathrm{W}/\text{cm}}^2$.