Abstract-Flexible and giant terahertz modulation based on ultra strain sensitive conductive polymer composites

Qiwu Shi, Ke Tian, Hongfu Zhu, Zi-run Li, Li-Guo,  Zhu Hua,  Deng Wanxia Huang, Qiang Fu,

https://pubs.acs.org/doi/10.1021/acsami.9b21890

Dynamic tuning of terahertz (THz) wave has a great potential application for smart THz devices, such as switching, modulation, sensor, and so on. However, realization of flexible THz modulation with high efficiency is rarely observed, which is nearly absent from the booming development and demands on flexible electronics. Here, we report a flexible THz modulation based on conductive polymer composites composed of thermoplastic polyurethane (TPU) and conductive particles (Ni). By designing the additive content of Ni particles, such flexible layer exhibits resistivity change of 6-7 orders under tensile strain, due to the formation of electron transport channel provided by in situ evolution of Ni network. It could be used to dynamically control THz transmission with giant modulation depth of around 96%, at high strain operation (up to around 58.5%). Moreover, these characteristics are demonstrated to be available for highly tension sensitive THz spectroscopy and imaging. This work opens up a connection between flexible polymer based composites and THz dynamic device. It proposes an unprecedented flexible THz modulation with giant tuning efficiency, and provides a scheme for contactless and passive tension sensor.