Rapid Fabrication of Silica Microlens Arrays via Glass 3D Printing

Transparent and Robust Superhydrophobic Structure on Silica Glass Processed with Microstereolithography Printing

Silica glass devices are widely used due to their exceptional physical and chemical properties. However, prolonged usage may result in abrasion and contamination of silica glass devices, adversely affecting the service life. One of the most effective solutions to this issue is surface modification, in which superhydrophobicity with high transmittance and mechanical robustness is highly desired. Inspired by the concept of protective armor, we proposed a novel approach for the direct integration of robust and transparent superhydrophobic structures on silica glass. In this method, microstereolithography synergistic heat treatment processes are used to create a micrometer-scale biomimetic frame on the surface of silica glass and then filled with in situ deposited nanoparticles. The superhydrophobicity of the surface can be obtained through the nanoparticles, and the biomimetic frame can protect the surface from direct contact with external objects to achieve durability. This process allows the preparation of superhydrophobic silica structures on the silica device surface at temperatures below its melting point, which prevents any damage to the devices during the heat treatment. Moreover, up to 90% transmittance does not affect the performance of silica devices. The composite structure maintains a contact angle of over 150° after multiple abrasion tests, verifying the mechanical robustness. This innovative process paves the way for forming a high mechanical robustness and excellent transmittance protective layer on silica glass devices, which expands the application field.

Laser-Induced Fabrication of Micro-Optics on Bioresorbable Calcium Phosphate Glass for Implantable Devices

In this study, a single-step nanosecond laser-induced generation of micro-optical features is demonstrated on an antibacterial bioresorbable Cu-doped calcium phosphate glass. The inverse Marangoni flow of the laser-generated melt is exploited for the fabrication of microlens arrays and diffraction gratings. The process is realized in a matter of few seconds and, by optimizing the laser parameters, micro-optical features with a smooth surface are obtained showing a good optical quality. The tunability of the microlens' dimensions is achieved by varying the laser power, allowing the obtaining of multi-focal microlenses that are of great interest for three-dimensional (3D) imaging. Furthermore, the microlens' shape can be tuned between hyperboloid and spherical. The fabricated microlenses exhibited good focusing and imaging performance and the variable focal lengths were measured experimentally, showing good agreement with the calculated values. The diffraction gratings obtained by this method showed the typical periodic pattern with a first-order efficiency of about 5.1%. Finally, the dissolution characteristics of the fabricated micropatterns were studied in a phosphate-buffered saline solution (PBS, pH = 7.4) demonstrating the bioresorbability of the micro-optical components. This study offers a new approach for the fabrication of micro-optics on bioresorbable glass, which could enable the manufacturing of new implantable optical sensing components for biomedical applications.