基于电控超薄层氮化钛的动态偏振调控超表面研究

可重构超表面对电磁波的动态操纵具有广泛的应用前景，尤其是，近红外波段的动态偏振调控在光信息通讯、传感探测和光谱检测等领域具有迫切的应用需求。然而，构成近红外波段可重构超表面的可调材料种类较少且性能不佳。针对这个问题，本项目拟将电控可调的超薄层氮化钛(TiN)引入到近红外波段可重构超表面的设计中，探索超薄层TiN的电学调控规律，建立调控电压与载流子浓度的对应关系；探究超薄层TiN手性阵列中量子效应及其对动态偏振调控的影响；构建超薄层TiN-Au复合的对称破缺超表面和相位梯度超表面，通过电控超薄层TiN的载流子浓度调制等离激元共振波长和模式特性，实现可调谐的圆偏振滤波器和多功能的偏振转换器。项目成果将为可见光和近红外等较短波段可重构超表面设计提供新思路，推动可重构超表面器件的发展和应用。

The dynamic electromagnetic manipulation via reconfigurable metasurfaces has wide application potentials. Especially, dynamic polarization control in the near-infrared waveband is highly desired for the urgent requirements in the applications of optical information communication, sensing detection, spectrum detection, ect.. However, the tunable materials for constructing reconfigurable metasurfaces in the near-infrared waveband are type-limited, and the performances are not good enough. To solve this problem, electrically tunable ultrathin TiN films will be introduced into the design of reconfigurable metasurfaces in the near-infrared band in this project. Specifically, the electrical tuning regulation of ultrathin TiN films will be investigated, and the quantitative relations between gating voltages and carrier densities will be established. Also, the quantum effects of ultrathin TiN chiral arrays and their influences in dynamic polarization control will be investigated. Furthermore, the symmetry-broken and the phase gradient metasurfaces, which support the excitations of plasmon resonances, will be designed by combining ultrathin TiN films with Au patterns. And the resonant wavelength and mode characteristics of plasmon resonances will be adjusted by electrically gating ultrathin TiN films. Thus, wavelength-tunable circular polarization filters and multifunctional polarization converters will be realized. The successful implementation of this project would pave a new way to design reconfigurable metasurfaces in the visible and near-infrared wavebands, which will accelerate the development and application progress of the reconfigurable metasurface devices.