The study aims to understand the carbonization mechanism when an ns NIR transparent fiber laser beam irradiation of polycarbonate (PC) instead of irradiation using a UV laser beam or ultrashort pulsed laser beam. It reveals that PC can be decomposed with an ns transparent 1064 nm laser beam. The laser fluence threshold under which to cause ablation in PC was not a constant value. The threshold decreased as the scanning pulse number increased. The threshold fluence was above 2.9 J/cm2 at irradiation with 10 pulses. The threshold fluence was above 11.6 mJ/cm2 at irradiation with 2 pulses. The optical transmittance of PC was decreased under laser irradiation. The optical transmittance was reduced by 50% and 90% at laser fluence of 2.9 J/cm2 and 11.6 J/cm2, respectively, at irradiation with 15 pulses. In addition, x-ray photoelectron spectroscopy measurements show that the C/O ratio was reduced 20.8% and 33.2%, respectively. The water contact angle was reduced due to the carbon loss at the PC surface. Inside marking of PC produced a darker contrast than surface marking due to that the carbon was lost at the surface, in contrary, carbonate concentration remained when marking inside the bulk of PC.

中文翻译：

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透明聚碳酸酯光纤激光辐照研究

该研究旨在了解使用 ns NIR 透明光纤激光束照射聚碳酸酯 (PC) 而非使用紫外激光束或超短脉冲激光束照射时的碳化机制。它表明 PC 可以用 ns 透明的 1064 nm 激光束分解。在 PC 中引起烧蚀的激光能量密度阈值不是一个恒定值。阈值随着扫描脉冲数的增加而降低。在用 10 个脉冲照射时，阈值能量密度高于 2.9 J/cm2。在用 2 个脉冲照射时，阈值能量密度高于 11.6 mJ/cm2。PC 的透光率在激光照射下降低。在 2.9 J/cm2 和 11.6 J/cm2 的激光能量密度下，在 15 个脉冲的照射下，光透射率分别降低了 50% 和 90%。此外，X 射线光电子能谱测量表明，C/O 比分别降低了 20.8% 和 33.2%。由于 PC 表面的碳损失，水接触角减小。由于碳在表面丢失，PC 的内部标记产生比表面标记更暗的对比度，相反，当在 PC 内部进行标记时，碳酸盐浓度仍然存在。