Light-Matter Complex Interactions in Stereolithographies

Since its inception in 1984, 3D printing has revolutionized manufacturing by leveraging the additivity principle and simple material-energy coupling. Stereolithography, as the pioneering technology, introduced the concept of photopolymerization with a single photon. This groundbreaking approach not only established the essential criteria for additive processes employing diverse localized energies and materials, including solid, pasty, powdery, organic, and mineral substances, but also underscored the significance of light-matter interactions in the spatial and temporal domains, impacting various critical aspects of stereolithography's performance. This review article primarily focuses on exploring the intricate relationship between light and matter in stereolithography, aiming to elucidate operational control strategies for fabrication processes, encompassing voxel size manipulation. Furthermore, advancements in light excitation modes, transitioning from one-photon to two-photon mechanisms, have unlocked new material and creative possibilities. Notable advantages include the elimination of layering (true 3D printing) and the ability to fabricate objects using silica glass. Although these volumetric 3D printing methods deviate from conventional additive manufacturing concepts and possess narrower application scopes, they offer reduced manufacturing and design timeframes along with enhanced spatial resolution in select cases. These complex light-matter interactions form the cornerstone of this comprehensive review, shedding light on operational control strategies and considerations in stereolithography. By comprehensively analyzing the impact of light-matter interactions, including the novel two-photon excitation, this review highlights the transformative potential of stereolithography for rapid and precise fabrication. While these techniques may occupy a smaller niche within the broader spectrum of 3D printing technologies, they serve as valuable additions to the array of 3D devices available in the market.