3D Femtosecond Laser Beam Deflection for High-Precision Fabrication and Modulation of Individual Voxelated PCM Meta-Atoms.

Optical metasurfaces have found widespread applications in the field of optoelectronic devices. However, achieving dynamic and flexible control over metasurface functionalities, while also developing simplified fabrication methods for metasurfaces, continues to pose a significant challenge. Here, the study introduces a PCM-only metasurface that exclusively consists of voxel units crafted from different phases of phase-change materials. Micro-nano regions, with varying phase states, are directly utilized as resonant elements and embedded in the material, forming the metasurface voxel meta-atoms. By manipulating the morphology, size, and arrangement of these meta-atoms, the study achieves both the fabrication and modulation of the PCM-only metasurface. Additionally, a 3D high-precision voxelated beam deflection method based on femtosecond laser phase modulation is introduced to streamline the fabrication and modulation of PCM-only metasurface. By using a spatial light modulator to load the blazed grating phase manipulation beam for precise deflection, high-precision deflection processing of individual meta-atom on metasurfaces can be achieved, with a deflection accuracy of up to 200nm. By loading Fresnel phase manipulation beams to move along the z-axis, perfect modulation of PCM sub-meta-atoms can be achieved. The 3D femtosecond laser beam deflection technology will bring many potential application opportunities in the fields of optoelectronic device fabrication and functional control.