Confocal Laser Scanning Microscopy for Investigation of Up-to-Micrometer-Scale 3D Components Fabricated by Direct Laser Writing-Lithography Methods (Review)

Advanced characterization of 3D microstructures is critical for applications in optics, photonics, and biomedicine. Confocal laser scanning microscopy (CLSM) has emerged as a key technique for non-destructively characterizing microstructures fabricated via direct laser writing (DLW) lithography. CLSM offers high resolution and contrast scanning, simplified sample preparation and easy to operate, as well as lower cost compared to electron microscopy. In addition, CLSM allows rapid acquisition of longitudinal and cross-sectional images at any position in 3D microstructures. This review summarises recent CLSM applications for investigation of fabricated DLW microstructures. We discuss CLSM approaches for visualising internal microstructures, surface analysis, and the investigation of material properties. Furthermore, we discuss the utilization of CLSM in case studies of fabricated DLW microstructures for different applications. Finally, we provide our thoughts on future directions for CLSM integration with advanced fabrication techniques to expand characterization capabilities. Hence, we hope that this review will provide a fruitful insight for research communities in optical engineering, photonics, and materials science.