Abstract-Dynamic Photo-induced Controlling of the Large Phase Shift of Terahertz Waves via Vanadium Dioxide Coupling Nanostructures

Yuncheng Zhao, Yaxin Zhang, Qiwu Shi, Shixiong Liang, Wanxia Huang, Wei Kou, Ziqiang Yang,

https://pubs.acs.org/doi/abs/10.1021/acsphotonics.8b00276?mi=aayia761&af=R&AllField=nano&target=default&targetTab=std

Utilizing terahertz (THz) waves to transmit data for communication and imaging places high demands on phase modulation. However, until now, realizing a large phase shift using a one-layer structure in transmission mode has been difficult. In this paper, utilizing a composite unit cell by coupling the traditional metallic wire dipolar resonance and the split-ring capacitive inductance resonance results in an enhanced resonance coupling mode. Combined with a vanadium dioxide (VO2) nanostructure and applying the photo-induced phase transition, the resonant intensity of the mode can be dynamically controlled, which leads to an ultralarge phase shift in the incident THz wave. The dynamic experimental results show that controlling the power of the external laser can achieve a phase shift of up to 138 degrees near 0.6 THz using this one-layer VO2 nested composite structure. Moreover, within a 55 GHz (575 GHz-630 GHz) bandwidth, the phase shift exceeds 130 degrees. This attractive phase shift modulation may provide prospective applications in THz imaging, communications, etc.