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.

The continuous phase plate (CPP) is the vital diffractive optical element involved in laser beam shaping and smoothing in high-power laser systems. The high gradients, small spatial periods, and complex features make it difficult to achieve high accuracy when manufacturing such systems. A high-accuracy and high-efficiency surface topography manufacturing method for CPP is presented in this paper. The atmospheric pressure plasma jet (APPJ) system is presented and the removal characteristics are studied to obtain the optimal processing parameters. An optimized iterative algorithm based on the dwell point matrix and a fast Fourier transform (FFT) is proposed to improve the accuracy and efficiency in the dwell time calculation process. A 120 mm × 120 mm CPP surface topography with a 1326.2 nm peak-to-valley (PV) value is fabricated with four iteration steps after approximately 1.6 h of plasma processing. The residual figure error between the prescribed surface topography and plasma-processed surface topography is 28.08 nm root mean square (RMS). The far-field distribution characteristic of the plasma-fabricated surface is analyzed, for which the energy radius deviation is 11 μm at 90% encircled energy. The experimental results demonstrates the potential of the APPJ approach for the manufacturing of complex surface topographies.

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.