Dual-wavelength multiplexed metasurface holography based on two-photon polymerization lithography.

Two-photon polymerization (TPP) lithography can process 3D micro-nano structures with high precision and has wide applications in the fields of micro-optics. Metasurfaces can flexibly control electromagnetic fields at subwavelength scale, achieving functions such as multidimensional multiplexing holography and achromatic imaging. Meta-devices are usually fabricated via EBL-based process, which is complex and difficult to fabricate meta-devices composed of meta-atoms with different heights. Here, we design a color dual-wavelength metasurface hologram without spatial multiplexing. By combining the propagation phase and the geometric phase, the phase response of two wavelengths is achieved in the same polarization state, and the metasurface is prepared using TPP 3D laser printing technology. The experimentally reconstructed images are consistent with theoretical predictions. This not only verifies the feasibility of this 3D printing technology in the preparation of metasurface samples operating in visible band but also provides potential applications in holographic display, optical encryption, anticounterfeiting, and other fields.