不锈钢表面陷光微结构的纳秒激光制备

Fabrication of Light Trapping Microstructures on Stainless Steel Surface by Nanosecond Laser

利用纳秒激光微加工技术在316L不锈钢表面制备了微孔阵列结构，实现了金属表面200~900 nm波长范围内光波的吸收增强。获得的微孔结构的直径和深度取决于激光的单脉冲能量和累积脉冲数。单脉冲能量相同时，随累积脉冲数的增加，孔深/孔径比增加，脉冲次数超过1200时，比值趋于稳定。相同累积脉冲数条件下，单脉冲能量越小，孔深/孔径比越大。通过表面光反射率测试对微结构的陷光性能进行了评价，在微孔投影面积占总面积的比例相等、脉冲次数相同的条件下，单脉冲能量越小，所得微孔阵列结构的陷光能力越强。初步探讨了微孔结构特征的形成原因，以及微结构在提高金属表面陷光性能中的作用。

The micropore array structure is fabricated by nanosecond laser on 316L stainless steel surface. The microstructured metal surface shows a great absorption enhancement with a wavelength range of 200~900 nm. The diameters and heights of the micropores depend on the single laser pulse energy and laser pulse number. With the increase of the laser pulse number, the depth/diameter ratio of the micropore increases, and the ratio tends to be stable when the pulse number is more than 1200. With the same pulse number, the weaker the single pulse energy is, the larger the depth/diameter ratio is. The optical absorption properties of the microstructures are estimated by the surface light reflectivity test. For the same ratio of the micropore projected area to the total area and the same pulse number, the lower the single pulse energy is, the stronger the light trapping ability of the micropore array structure is. The formation mechanisms of the micropores and the roles of these micropores in changing metal-surface optical absorption are preliminarily discussed.