The advancement of modern optical imaging systems has generated a substantial demand for precision-engineered imaging components with complex functionalities. Despite various micro-nanofabrication techniques demonstrating significant advantages over traditional methods, critical challenges persist in achieving nanoscale resolution and freely designed intricate micro-optical structures. Femtosecond direct laser writing (FsDLW) emerges as a pivotal solution to these challenges, facilitating the fabrication of sophisticated architectures that transcend the diffraction limit through nonlinear multiphoton absorption. This technique processes exceptional capabilities, including extensive material compatibility, versatile micro-nanoscale fabrication, and true three-dimensional structuring. To date, FsDLW has been successfully employed in the manufacturing of diverse micro-optical imaging components. This review systematically elucidates the fundamental methodologies of FsDLW applicable to micro-optical device fabrication, alongside a comprehensive overview of the relevant material systems. Furthermore, recent advancements in micro-optical imaging devices and their emerging applications are critically assessed. Finally, we provide a prospective analysis of unresolved challenges and future research directions for imaging optical components.

Nano-3D printing has obtained widespread attention owing to its capacity to manufacture end-use components with nano-scale features in recent years. Multiphoton lithography (MPL) is one of the most promising 3D nanomanufacturing technologies, which has been widely used in manufacturing micro-optics, photonic crystals, microfluidics, meta-surface, and mechanical metamaterials. Despite of tremendous potential of MPL in laboratorial and industrial applications, simultaneous achievement of high throughput, high accuracy, high design freedom, and a broad range of material structuring capabilities remains a long-pending challenge. To address the issue, we propose an acousto-optic scanning with spatial-switching multispots (AOSS) method. Inertia-free acousto-optic scanning and nonlinear swept techniques have been developed for achieving ultrahigh-speed and aberration-free scanning. Moreover, a spatial optical switch concept has been implemented to significantly boost the lithography throughput while maintaining high resolution and high design freedom. An eight-foci AOSS system has demonstrated a record-high 3D printing rate of 7.6 × 10⁷ voxel s⁻¹, which is nearly one order of magnitude higher than earlier scanning MPL, exhibiting its promise for future scalable 3D nanomanufacturing.