飞秒激光不锈钢表面陷光微结构的制备与性能研究

Prepartion and property of stainless steel antireflection surface microstructured with a femtosecond laser

利用飞秒激光在高真空环境下，在316L不锈钢表面两次交叉扫描制备了周期性微纳结构，并研究了微纳结构对波长范围200～900nm的光波的吸收增强能力。样品表面微结构形貌与成分采用扫描电子显微镜（SEM）和X射线衍射仪测试。第1次扫描采用高能流激光，获得了微米级锥状钉结构，表面覆盖了典型的激光诱导周期性表面结构（LIPSS）。然后将样品旋转90°，采用能流为0．02J／cm^2的激光进行第2次扫描，路径与第1次扫描相交。第1次扫描的结构中的LIPSS被第2次低能流激光打断纳米颗粒，从而与锥状钉结构结合形成双尺度微结构。反射率测试结果表明，这种双尺度微结构表面的平均反射率约为2．28％，为光滑表面平均反射率的3．42％。结合xRD分析结果，不锈钢表面获得强陷光性能主要归因于飞秒激光制备的微结构。

The stainless steel surfaces were microstructured with a two-step femtosecond laser in high vacuum environment, and antireflection capability in a wavelength range of 200-900 nm was investigated. The micro- structures of the stainless steel surfaces were studied by the scanning electron microscopy and the X-ray diffrac- tion. In the first scanning with high laser fluence, periodic spikes on micron scale covered with typical laser-in- duced periodic surface structures （LIPSS） were obtained. The sample was then rotated 90°, and the second scanning was performed with laser fluence of 0.02J/cm2 intersecting the first treated region. With this two-step laser cross scanning method, the double-scale structure namely micron spikes covered with submicron particles were obtained on the stainless steel surface. The reflectance tests showed that the average reflectance of the double-scale structure was about 2.28 %, which was only approximately equal to 3.42% of that of the polished stainless steel surface. Chemical analysis by X-ray diffraction indicates that blackness of stainless steel surfaces was attributed to the microstructures formed by femtosecond laser instead of the change in elemental composi- tlon.