Diatomic metasurface for multi-functional light field manipulation

Metasurface composed of arrays of subwavelength scale optical antennas emerges as a new paradigm for light field manipulation and unpins various flat optical diffractive devices. Based on their phase modulation mechanisms, the reported metasurfaces can be classified into three categories: resonance phase, propagation phase and geometric phase. In this talk, we propose a new metasurface design allowing to fully control the phase, amplitude, polarization and frequency of visible light simultaneously. This is achieved through a generalized geometric phase mechanism which combines the detour phase and the Pancharatnam–Berry phase. Utilizing a diatomic design strategy, the in-plane displacements and orientations of two identical meta-atom in each unit meta-molecules are fully exploited enabling light field manipulation at multi-dimensions. Leveraging this appealing feature, we experimentally demonstrated the broadband vectorial holographic images with spatially-varying polarization states, dual-way polarization switching functionalities, and full-color complex-amplitude vectorial holograms. Our work may suggest a new route to achromatic diffractive elements, polarization optics and ultra-secure anti-counterfeiting.