Terahertz Nonlinear Superconducting Metamaterials

TL;DR

This paper demonstrates a terahertz-frequency nonlinear superconducting metamaterial made from NbN, showing giant amplitude modulation due to nonlinear effects, with potential for novel applications in nonlinear metamaterials.

Contribution

It introduces a superconducting metamaterial with strong nonlinearities at terahertz frequencies, highlighting temperature-sensitive nonlinear behaviors distinct from heating effects.

Findings

Giant amplitude modulation observed due to nonlinearities

Nonlinear behaviors detectable at various temperatures

Resonance modulation differs from heating effects

Abstract

We investigate the nonlinear effect of a planar superconducting metamaterial made from niobium nitride (NbN) at terahertz frequencies. As the variation of the incident intense terahertz field alters the intrinsic conductivity in the NbN, a consequent giant amplitude modulation is observed due to the strong nonlinearities. The high sensitivity of the chosen metamaterial even allows observing the nonlinear behaviors at various temperatures, but the resonance modulation induced by the nonlinear effect was distinct from that induced by the heating effect. The presented results illustrate a clever implementation of strongly enhanced nonlinearities and thus may bring nonlinear metamaterials into novel applications.