The team of researcher Wei Chaoyang of Shanghai Optical Machinery Institute has realized the manufacture of fused quartz components with high resistance to UV laser damage

Recently, a team led by researcher Zhaoyang Wei of the Precision Optics Manufacturing and Testing Center of the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, has realized the manufacture of fused quartz components with high resistance to UV laser damage based on the defect characterization and removal process of CO2 laser. The research is published in Light: Advanced Manufacturing.

The problem of UV laser induced damage of fused quartz elements seriously restricts the development of high power laser systems. Due to the inevitable processing defects in the current contact polishing process, and it is difficult to be completely removed by post-processing, the service performance and life of fused quartz components are greatly reduced.

The research team proposed a laser chromatography ablation method to characterize subsurface defects based on microsecond pulsed laser low stress uniform ablation technology, and coupled it to the rapid material removal process to achieve complete removal of subsurface defects in the grinding stage. After that, the CO2 laser laser full link flexible machining of fused quartz components is realized by using laser conformal cleaning method to clean the redeposited contaminants on the ablative surface, and using laser melting polishing to smooth the ablative trajectory.

Compared with the traditional process, the CO2 laser processing link can effectively inhibit the introduction of machining defects and realize the preparation of fused quartz components with higher damage threshold. The laser-based defect characterization and removal method proposed in this study provides a new tool for the study of subsurface defects and the formulation of suppression strategies, and also provides a new idea for the low-defect machining of fused quartz components.

This work was supported by the National Key Research and Development Program, Shanghai Sailing Program, National Natural Science Youth Foundation, Shanghai Natural Science Foundation, Astronomy Joint Foundation and Youth Innovation Promotion Association of Chinese Academy of Sciences.

Figure 1 (a) Traditional process link; (b)CO2 laser processing link; (c) Three-dimensional full aperture subsurface defect characterization method

FIG. 2 Comparison of damage properties between conventional and laser-based samples: (a)1-on-1 damage probability (355nm, 8.3ns); (b) Typical damage morphology

Source: Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences