Active metasurfaces enable dynamic manipulation of the scattered electromagnetic wavefront by spatially varying the phase and amplitude across arrays of subwavelength scatterers, imparting momentum to outgoing light. Similarly, periodic temporal modulation of active metasurfaces allows for manipulation of the output frequency of light. Here we combine spatial and temporal modulation in electrically modulated reflective metasurfaces operating at 1,530 nm to generate and diffract a spectrum of sidebands at megahertz frequencies. Temporal modulation with tailored waveforms enables the design of a spectrum of sidebands. By impressing a spatial phase gradient on the metasurface, we can diffract selected combinations of sideband frequencies. Combining active temporal and spatial variation can enable unique optical functions, such as frequency mixing, harmonic beam steering or shaping, and breaking of Lorentz reciprocity.

有源超表面通过在空间上改变亚波长散射体阵列的相位和振幅，从而为出射光提供动量，从而实现对散射电磁波前的动态操纵。同样，有源超表面的周期性时间调制允许操纵光的输出频率。在这里，我们在 1,530 nm 工作的电调制反射超表面中结合了空间和时间调制，以产生和衍射兆赫兹频率的边带光谱。具有定制波形的时间调制支持边带频谱的设计。通过在超表面上施加空间相位梯度，我们可以衍射选定的边带频率组合。将主动时间和空间变化相结合可以实现独特的光学功能，例如混频、谐波光束控制或整形以及打破洛伦兹互易性。