Spatio-temporal light-thermal synergistic regulation for high-fidelity photocuring imprinting of thick-walled silica glass components

Ultraviolet (UV) photocuring imprinting technology enables the efficient and high-fidelity fabrication of silica glass micro/nanostructures under room-temperature and low-pressure conditions, showing unique advantages for the manufacturing of complex silica glass optical components. However, thick-walled silica glass components are highly prone to cracking during the forming process, which severely restricts the extension of this technology to the fabrication and application of thick-walled silica glass components. To address this issue, this study first elucidates the physical origin of internal-stress instability in thick-walled photocuring systems. A light-thermal synergistic regulation manufacturing strategy is then proposed innovatively. The strategy mitigates stress accumulation from three dimensions. The photoinitiator concentration is optimized to balance the photoinitiation efficiency and penetration depth. A sequential bidirectional exposure process assisted by a customized light shield is introduced to flatten the optical energy gradient. A dynamic preheating treatment at 60 °C is applied to broaden the stress-relaxation window and alleviate the polymerization exotherm peak. The experimental results show that this strategy successfully produces crack-free green bodies with thickness up to 7 mm. After thermal treatment, dense and transparent silica glass components were obtained, exhibiting a visible-light transmittance of 92% and a nearly uniform through-thickness Vickers hardness of approximately 1205 HV, both comparable to those of commercial fused silica glass. The synergistic strategy is further extended to the fabrication of a near-square-aperture lens array, achieving nearly isotropic shrinkage of the array structure and high-fidelity transfer of the lens surface profile. The fabricated lens arrays exhibit excellent beam homogenization and focusing imaging performance. This study overcomes the thickness limitation of ultraviolet photocuring imprinting technology for silica glass fabrication and provides a feasible route for the structure-function integrated manufacturing of silica glass components with both thick bulk features and complex microscopic surface precision.