Strain Sensitivity of Electric-Magnetic Coupling in Flexible Terahertz Metamaterials

In order to investigate the effects of bending strain on electric-magnetic coupling, we fabricated and characterized two types of flexible terahertz (THz) metamaterials on polyethylene naphthalate (PEN) substrates, which had either asymmetric or symmetric configuration. The asymmetric flexible THz metamaterials showed a plasmon-induced transparency originating from electric-magnetic coupling. The transparency was rather robust and insensitive to strain. The symmetric metamaterials demonstrated a transmission dip at a frequency of 1.35 THz without applied strain due to electric resonance. However, if strain gradually varied, a continuously tunable transmission dip was observed at a frequency of 1.1 THz, which could be ascribed to electric-magnetic coupling induced by symmetry breaking. The promising results suggested that the asymmetric and the symmetric flexible THz metamaterials could find potential applications in curved devices and remote stress sensors, respectively.This work was supported by the National Natural Science Foundation of China (11104290, 11204146), the Qianjiang Talent Program (2013R10083), and Ningbo Key Laboratory of Silicon and Organic Thin Film Optoelectronic Technologies