Cross‐Scale Patterned Pulse Laser Lithography for MIM Meta‐Devices Processing

Abstract Metal‐insulator‐metal (MIM) meta‐devices have attracted attention for their low Ohmic losses and small aspect ratio of structures in meta‐device design and manufacturing. It is still challenging to achieve high‐resolution, large‐scale, and uniform freeform micro‐/nanostructures on film surfaces. Ultrafast laser processing offers a promising solution, excelling in efficiency and the tunability of processed structures. However, it struggles to simultaneously achieve high resolution and high efficiency in direct writing. Here, a cross‐scale patterned pulse laser lithography method is developed to transform single spot into complex freeform pattern in a single ablation using a spatial light modulator. By modifying the optical propagation system, the maximum single‐ablation area is extended over 100 × 100 µm² and maintain the near diffraction limitation ablation resolution, realizing cross‐scale manufacturing. The beam intensity is homogenized by employing Gaussian‐compensate masks, avoiding patchy ablation of the delicate thin film structure caused by uneven energy distribution. For the design of MIM meta‐devices, 20 nm structured Ge₂Sb₂Te₅ top layer, which helps is used to achieve a near half‐wave phase delay, addressing the insufficient phase delay in single‐layer films. Furthermore, demonstrations of various centimeter‐scale MIM meta‐devices are conducted, realizing functions such as beam splitters and holographic displays, showcasing exceptional optical manipulation and fabrication efficiency.