双激光制备双层结构类金刚石膜的实验研究

利用飞秒激光和纳秒激光分别在氧气氛环境和高真空环境中烧蚀石墨靶材，在硅基底上获得了两种不同的类金刚石膜，通过红外透过曲线的拟合，获得了各自的光学参数；进而设计和制备了不同厚度组合的双层结构类金刚石膜硅基底样品:飞秒激光在氧气氛环境中制备的类金刚石膜具有低折射率、高透过性的特点，所以将其作为双层膜的内层，发挥其红外增透效能；纳秒激光在高真空环境中制备的类金刚石膜具有高硬度、耐蚀性的特点，所以将其作为双层膜的外表层，发挥其抗划、耐蚀的功能。实验测试表明:随着外表保护层厚度的增加，样品的中红外平均透过率逐渐下降0.5%~3%，表面硬度提高7.2~24.7 GPa。碱溶液浸泡试验表明，外表保护层能够承受碱溶液腐蚀，但过薄的保护层不能阻止溶液向膜层内部的渗透，从而使得不具有耐蚀性的红外增透层被腐蚀。研究结果为不同应用目的的双层膜或多层膜结构的设计与制备提供了实验基础。

Experiment research on the double-layer diamond-like carbon film prepared by double laser beams

A femtosencond laser and a nanosecond laser were used to ablate the graphite target in the oxygen atmosphere and high vacuum respectively, and two kinds of diamond-like carbon films were prepared on the silicon substrates. Then their optical constants were estimated by fitting the infrared transmissivity curves. Double-layer diamond-like carbon film with different thickness combinations on the silicon samples were designed and prepared:the layer deposited by femtosencond laser in the oxygen atmosphere was taken as the infrared anti-reflective layer because of its low refractive index and high transmissivity; the layer deposited by nanosecond laser in the high vacuum was taken as the protective layer based on its high hardness and corrosion resistance. The tests show that transmissivity of the samples in the medium infrared band decreases by 0.5%~3% and the surface hardness of the samples increases by 7.2-24.7 GPa when the thickness of the protective layer increases. Results of the corrosion resistance tests show that the protective layer has the well corrosion resistance, but it can not prevent the alkaline liquor from soaking into the deeper depth to corrupt the lower anti-reflective layer if the thickness of the protective layer is very thin. The research result can offer the experiment basis for the designs of double-layer or multi-layer films in the different fields.