Development of removal process of carbon contaminated broadband optical components****

大学-工业项目的目标是开发宽带光学元件碳污染的去除工艺。这包括François Légaré教授的INRS-ÉMT团队与量子谷投资（QVI）技术人员之间的合作。碳污染光学是同步辐射光束线装置上的一个常见问题，其中高能VUV光子束在高真空下传播使含有碳原子的残余分子（例如：CO2、CH 4）解离。在许多操作循环之后，光束线的光学部件将在其表面上积累碳层并降低性能。通过超短脉冲激光技术的最新发展，激光束线具有更大的强度和平均功率，在光学镜表面也观察到碳污染，并成为激光系统工作占空比的严重限制因素。在这种情况下，碳污染与入射激光脉冲的强度有关。待开发的去除工艺必须与高损伤阈值宽带介质镜兼容，该介质镜由30多个交替的介质层（例如SiO2、HfO 2和TiO 2）组成。由于这些反射镜的复杂性，它们本质上比同步加速器光束线光学器件更脆弱。使用位于INRS-ÉMT的ALLS设施，我们将污染位于真空室中的宽带光学介质镜，并分析碳层的结构。对现有的基于臭氧光解的除碳工艺进行了研究，并将其应用于宽带光学反射镜。将建造一个使用已确定的除碳工艺的原型清洁站，以清洁大型光学器件。在整个项目中，QVI将获得在真空条件下暴露于高强度超短脉冲的光学元件的修复知识和能力。这将使QVI能够优化位于其工厂的激光系统的停机时间和运营成本。**

The goal of the university-industry project is to develop a removal process for carbon contaminated of broadband optical components. This consist of a collaboration between the INRS-ÉMT team of Prof. François Légaré and technical staff of Quantum Valley Investments (QVI). Carbon contaminated optics is a common problem on synchrotron beam-lines facilities, in which a beam of energetic VUV photons propagating under high vacuum dissociates residual molecules containing carbon atoms (ex: CO2, CH4). After many operating cycles, the optical components of the beamline will accumulate layers of carbon on its surface and degrade the performance. Through recent development in ultrashort pulse laser technologies, where laser beamlines have greater intensity and average power, observation of carbon contamination has also been witnessed on surfaces of optical mirrors and becoming a severe limitation factor for the operational duty cycle of laser systems.****In this case, the carbon contamination is related to the intensity of the incident laser pulse. The removal process to be developed has to be compatible with high damage threshold broadband dielectric mirrors which are composed of over 30 alternating dielectric layers such as SiO2, HfO2 and TiO2. Due to the complexity of these mirrors they are intrinsically more fragile compared to synchrotron beamlines optics. Using the ALLS facility located at INRS-ÉMT, we will contaminate broadband optical dielectric mirrors located in vacuum chambers and analyze the structure of the carbon layers. Study of known carbon removal process based on ozone photodissociation will be accomplished and adapted to broadband optical mirror. A prototype cleaning station using the identified carbon removal process will be built to clean large optics. Throughout this project, QVI will gain knowledge and capacity on reconditioning of optical elements that were exposed to high intensity ultrashort pulses under vacuum conditions. This will permit QVI to optimize the downtime and operating cost of the laser system located at their facility.**