Mechanically tunable broadband terahertz modulator based on high-aligned Ni nanowire arrays

We present a mechanically tunable broadband terahertz (THz) modulator based on the high-aligned Ni nanowire (NW) arrays. The modulator is a sandwich structure consisting of two polydimethylsiloxane layers and a central layer of high-aligned Ni NW arrays. Our experimental measurements reveal the transmittance of THz wave can be effectively modulated by mechanical stretching. The NW density in arrays increases with the strain increasing, which induced an enhancement in the absorption of THz wave. When the strain increases from 0 to 6.5%, a linear relationship is observed for the variation of modulation depth (MD) of THz wave regarding the strain, and the modulated range is from 0 to 85% in a frequency range from 0.3 THz to 1.8 THz. Moreover, the detectable MD is about 15% regarding the 1% strain change resolution. This flexible Ni NW-based modulator can be promised many applications, such as remote strain sensing, and wearable devices.