Spectral amplitude modulation and dynamic near-field displaying of all-silicon terahertz metasurfaces supporting bound states in the continuum
Jitao Li, Jie Li, Chenglong Zheng, Zhen Yue, Dingyu Yang, Silei Wang, Mengyao Li, Yating Zhang, Jianquan Yao
Abstract
The bound states in a continuum (BICs) are objective physical phenomena that defy conventional wisdom, and they exist in the radiating continuous spectrum but remain perfectly localized with non-radiation, which is different from the traditional bound states. In this paper, we report in theory and experiment the high thickness all-silicon terahertz (THz) metasurfaces supporting BIC and quasi-BIC, which is realized by simple pairs of elliptical pillars. Meanwhile, we used an extra optical pump to modulate the transmission amplitude difference between BIC and quasi-BIC metasurfaces, to complete the active control from “On” state to “Off” state. We utilize the abundant amplitude gradation of metasurfaces with different asymmetric degrees to develop the polarization-dependent THz near-field displaying application that can make the grayscale characteristics of a photograph reappear and also be dynamically controlled at On state to Off state.