AUTHOR=Yang Ruisheng , Fu Quanhong , Fan Yuancheng , Xu Jing , Zhu Wei , Cai Weiqi , Zhang Fuli TITLE=Actively Controlled Frequency-Agile Fano-Resonant Metasurface for Broadband and Unity Modulation JOURNAL=Frontiers in Physics VOLUME=9 YEAR=2021 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2021.739465 DOI=10.3389/fphy.2021.739465 ISSN=2296-424X ABSTRACT=

The active control to the local resonant mode of metasurface is a promising route for improving the operation bandwidth limitation of metasurface. Here, we propose and experimentally demonstrated the active tunabilities in a frequency-agile Fano-resonant metasurface. The metasurface with a pair of asymmetric split ring resonators is integrated with double varactor diodes for active control of the sharp Fano resonance. It is found that the sharp Fano-type spectrum appears due to the near-field interferences between the collective electric and magnetic dipole modes. The physical insight is revealed through local field analysis, multipole decomposition and temporal coupled-mode theory. It is also found that the metasurface can be employed as a broadband and unity modulator. Hopefully, our results could inspire sophisticated electrically controlled photonic devices with novel functions.