Recent advances in femtosecond direct laser writing of micro-optical imaging components

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.