Although CO₂ laser polishing of fused silica surfaces is considered a promising advanced processing technology, its application remains fundamentally limited by low- to mid-frequency waviness and surface figure errors. To address the critical need for enhanced performance of laser-processed fused silica components, this study investigated the formation law of the surface profile during CO₂ laser processing. Experimental results revealed the formation law governing the influence of processing parameters on surface morphology. A multivariate regression model was established to quantitatively correlate processing parameters with surface profile evolution, enabling prediction of profile errors with less than 5% deviation. Furthermore, an optimization strategy was proposed by introducing an annealing process, which reduced the surface profile error by more than 50% (from 56.94 μm to 23.18 μm). These findings provide both a theoretical basis and process guidance for the low-defect fabrication of fused silica components in high-power laser applications.

Enhancing the laser-induced damage resistance (LIDR) of fused silica components is crucial for improving the overall performance of large-scale laser systems. However, traditional optical manufacturing techniques, based on contact processing principles, inevitably lead to the generation of defects such as scratches and contamination during processing, which severely limit the improvement of component LIDR. To address this issue, this study employs a CO₂ laser to polish ground fused silica samples. Through experimental analysis of the influence of pre-treatment processes and laser processing parameters on the damage performance of the laser-polished samples, an optimized laser polishing process scheme was obtained. Fused silica samples processed using the optimized laser polishing scheme were compared with those treated by conventional polishing and etching in terms of damage performance. The results indicate that, compared to conventional polished and etched samples, the laser-polished samples exhibited an approximately 20% increase in damage threshold and a 76.4%~90.8% reduction in damage density. The damage performance of the laser-polished samples was significantly superior to that of conventional polished and etched samples. Through experimental analysis, this paper obtained an optimized laser polishing process scheme and confirmed the definitive role of CO₂ laser polishing in enhancing the LIDR of fused silica samples, providing technical support for the development of next-generation optical manufacturing technologies.

Femtosecond laser is well-suited for the precision processing of high-melting-point ceramics. However, the thermal cumulative effects of high-repetition-rate pulses inevitably lead to defects. At present, there is an absence of effective methodologies for accurately predicting the influence of thermal cumulative effects on defect formation within multiphysics field models. This paper proposes a methodology that takes into account heat loss due to ablation in a finite element model. The model is used to quantitatively calculate the thermal accumulation effects and their spatiotemporal evolution patterns during high-repetition-rate processing. The simulation results demonstrate that as the fluence and repetition frequency increase, the temperature gradient and thermal stress within the material exhibit an upward trend, with thermal stress increasing nonlinearly as the number of pulses increases. This paper proposes a thermal stress prediction model for drilling, which is based on multiphysics finite element simulation, and its purpose is to predict the thermal stress within the material during drilling. The prediction model suggests that, for a particular laser fluence, there exists a threshold of repetition frequency, which the thermal accumulation effect can be disregarded. When the number of pulses reaches 50, the thermal stress during processing reaches a maximum of 792 (zirconia ceramic) and 652 MPa (silicon carbide ceramic). The experimental results in this study provide further confirmation that high-repetition frequency can cause thermal defects in the material during processing, which validates the accuracy of the model.