亚波长减反射结构的激光诱导损伤机理研究

The Fresnel reflection of optics has affected negatively the stabily of high power or high energy laser system. Subwavelength antireflective structure has the potential advantages of high laser indure damage resistance because it often was fabricated by micro/nano processing technology directly on the substrate surface. Subwavelenth structure has properties of high mechanical performance, high thermal stability and does not introduce any impurities and other characteristics. Here we fabricate disorder subwavelength structure by maskless with reactive ion etching and order subwavelength structure by colloidal crystals with reactive ion etching. The mechanism of subwavelength structure to the electromagnetic field is studied theoretically, and the subwavelength structure with high damage threshold can be designed by adjusting the field intensity. The origin of damage precursor of subwavelenth structure was investigated. The relationship between the damage precursors and the damage behavior also will be analyzed. We also study the damage dynamics of subwavelength structures during the laser induced damage happened. Through the study, we can know the field intensity regulation law and damage mechanism of the subwavelength structure for high power laser, and promote the application of the sub wavelength micro nano structure strong laser field.

在高功率或高能激光系统中，光学元件的菲涅尔反射对于光学系统的稳定性，负载能力产生极大的影响。表面亚波长减反射结构因为通过微纳加工技术直接在基片表面加工制备，机械性能好、热稳定性高、不引入任何杂质等特点，具有高抗损伤性能的潜在优势。本项目基于等离子体诱导自掩模技术以及胶体晶体模板技术制备熔石英表面亚波长减反射结构。理论上研究微纳结构对光场的调控机制，通过调控光场强区的思路设计可能具有高损伤阈值的亚波长结构。研究亚波长结构特有的损伤前驱的种类及形成原因，分析这些损伤前驱与损伤行为之间的关系。研究亚波长结构在激光诱导损伤发生下的损伤动力学过程。通过该项研究认识表面亚波长结构对于强激光加载下的场强调控规律和损伤机理，推动亚波长微纳结构强激光领域的应用。

在高功率或高能激光系统中，光学元件的菲涅尔反射对于光学系统的稳定性，负载能力产生极大的影响。表面亚波长减反射结构因为通过微纳加工技术直接在基片表面加工制备，高机械性能好、热稳定性高、不引入任何杂质等特点，具有高抗损伤性能的潜在优势。本项目基于矢量衍射理论设计了针对不同波长的亚波长抗反射结构，分析了亚波长结构各项参数对光场调控的影响规律，并通过胶体晶体模板、金属随机掩模和自掩模技术制备了针对355nm、532nm和1064nm抗反射的亚波长结构。研究了亚波长结构的激光诱导损伤机理，分析了影响亚波长结构发生损伤的关键因素，包括由于反应离子刻蚀引入的氟碳沉积物等。通过优化后处理，532nm抗反射亚波长结构的激光诱导损伤阈值高于AMP处理样件。该项工作说明了超宽谱抗反射亚波长结构在高功率激光技术中具有较好的应用前景。