Dynamically controlling terahertz (THz) waves with an ultracompact device is highly desired, but previously realized tunable devices are bulky in size and/or exhibit limited light-tuning functionalities. Here, we experimentally demonstrate dynamic modulation on THz waves with a dielectric metasurface in mode-selective or mode-unselective manners through pumping the system at different optical wavelengths. Quasi-normal-mode theory reveals that the physics is governed by the spatial overlap between wave functions of resonant modes and regions inside resonators perturbed by pump laser excitation at different wavelengths. We further design/fabricate a dielectric metasurface and experimentally demonstrate that it can dynamically control the polarization state of incident THz waves, dictated by the strength and wavelength of the pumping light. We finally numerically demonstrate pump wavelength-controlled optical information encryption based on a carefully designed dielectric metasurface. Our studies reveal that pump light wavelength can be a new external knob to dynamically control THz waves, which may inspire many tunable metadevices with diversified functionalities.

动态超构表面是将可调元素集成到静态超构原子中，且功能受不同外部激励手段控制的超构表面。基于动态超构表面已经实现了各种可调器件，包括变频滤波器、吸收器，变焦透镜，动态光束控制器，动态全息元件等。首先对动态超构表面的调制方法进行系统的总结，然后对相关的研究工作进行综述。动态超构表面可以分为两类：一类是对所有超构原子进行统一控制的均匀调控动态超构表面，用于实现光谱、偏振和波前的动态转换；另一类是通过对超构原子进行独立控制的动态可重构/可编程超构表面，用于实现对波前的灵活调控。功能灵活可控的动态器件是超构表面未来研究的主要方向，对已有的动态器件进行了总结，并进一步讨论和展望了动态超构表面发展的方向及面临的挑战。